README.md

Go dataplane

This module is bound into megaproxy.aar with gomobile. It embeds tun2socks/gVisor, registers MASQUE (HTTP/3), HTTPS CONNECT and SSH direct-tcpip transports, protects every upstream socket through Android VpnService.protect, verifies HTTPS proxy certificates and SSH host keys, and uses uTLS for HTTPS ClientHello control. HTTPS with Jump nests a second HTTPS CONNECT transport inside the first, with independent TLS verification, authentication and HTTP/2 sessions. Only the jump is dialed directly; it resolves the destination proxy hostname. Application traffic counters exclude the intermediate tunnel. SSH with Jump creates a nested SSH client through the jump session. SSH transports support TCP; DNS is carried over DoH, while arbitrary UDP (including QUIC) is intentionally blocked. Start borrows the JVM-owned TUN descriptor for the call and duplicates it with CLOEXEC on entry. Go closes only its own duplicate; Java retains responsibility for the descriptor it passed. The bridge passes the Android TUN MTU explicitly (currently 1400). Generated gomobile types are compile-time JVM dependencies, so signature changes must compile on both sides.

Use the supported Fastlane commands from the repository root:

bundle exec fastlane android native_tests
bundle exec fastlane android native_fuzz
bundle exec fastlane android native_integration
bundle exec fastlane android debug_artifact

native_tests includes the Go race detector; native_fuzz runs a bounded 20-second parser campaign. native_integration requires Docker and exercises production dialers against real GOST/OpenSSH servers and a private HTTP/UDP origin. It runs in the native CI job, with no Android emulator. See the fixture and scenario details. Android build lanes prepare app/libs/megaproxy.aar through scripts/build-fdroid-native.sh, which installs the pinned gomobile/gobind version and uses the reproducible binding flags. Do not replace that build path with gomobile@latest. Go dependencies are pinned in go.mod and go.sum.

Requirements and environment setup are in the root README and the Fastlane reference. Native tests use local servers and synthetic file descriptors; they do not certify real Android TUN/JNI lifecycle behavior.

MASQUE uses uQUIC with protected UDP sockets and one shared HTTP/3 session. TCP uses CONNECT streams; UDP uses CONNECT-UDP with context ID zero. DNS still uses the existing DoH implementation. See the root README for GOST listener setup, fingerprint versions and UDP limitations. The pinned local uQUIC package closure retains uTLS 1.8.2; provenance and the integration patches are recorded in third_party/uquic/MEGAPROXY.md.

Optional HTTPS HTTP/3 preference also supports HTTPS Jump: nested QUIC travels through the first node's CONNECT-UDP association, with remote exit-host DNS. Both hops must support MASQUE and a usable path MTU. Otherwise the entire chain retains HTTPS/TCP through Jump. Credentials/certificate failures remain terminal; Firefox Jump falls back because its DATAGRAM limit is too small. Nested QUIC derives its path limit from the verified outer send/receive budgets and framing, then warms the exit path before selection, while retaining its TLS preset. Regression tests include site HTTP/3 flights and UDP payloads of 1280/1350 bytes, asymmetric MTU, packet loss, GOAWAY and cancellation during the exit handshake.