Initial commit: embedded Tailscale tsnet Flutter plugin for remote heater access

Go layer (c-archive) provides a localhost TCP proxy through a WireGuard tunnel. Flutter connects gRPC to localhost:PORT, Go forwards via tsnet to heater's Tailscale IP. No VPN entitlement needed — uses userspace netstack. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-14 05:13:55 -04:00
commit 2dbadcd8ed
16 changed files with 1931 additions and 0 deletions
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+// Standalone test for the tsnet proxy — verifies the Go layer works
+// without needing the Flutter app or iOS build.
+//
+// Usage:
+//   cd tailscale_kit/test
+//   go run tsnet_test.go \
+//     -authkey=tskey-auth-xxxxx \
+//     -heater-ip=100.x.x.x \
+//     -heater-port=5050
+//
+// This will:
+//   1. Join the Tailnet with the given auth key
+//   2. Open a local TCP proxy to the heater's Tailscale IP
+//   3. Make a raw TCP connection through the proxy to verify connectivity
+//   4. Print the result and clean up
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+	"time"
+
+	"tailscale.com/tsnet"
+)
+
+func main() {
+	authKey := flag.String("authkey", "", "Tailscale auth key for the phone/test client")
+	heaterIP := flag.String("heater-ip", "", "Heater's Tailscale IP (100.x.x.x)")
+	heaterPort := flag.Int("heater-port", 5050, "Heater's gRPC port")
+	flag.Parse()
+
+	if *authKey == "" || *heaterIP == "" {
+		fmt.Fprintf(os.Stderr, "Usage: go run tsnet_test.go -authkey=tskey-auth-xxx -heater-ip=100.x.x.x\n")
+		os.Exit(1)
+	}
+
+	// Create temp state dir
+	stateDir, err := os.MkdirTemp("", "tsnet-test-*")
+	if err != nil {
+		log.Fatalf("Failed to create state dir: %v", err)
+	}
+	defer os.RemoveAll(stateDir)
+
+	// Step 1: Start tsnet
+	log.Println("[1/4] Starting tsnet...")
+	s := &tsnet.Server{
+		Dir:       stateDir,
+		Hostname:  "constellation-test-client",
+		AuthKey:   *authKey,
+		Ephemeral: true, // don't persist for tests
+	}
+
+	if err := s.Start(); err != nil {
+		log.Fatalf("tsnet start failed: %v", err)
+	}
+	defer s.Close()
+
+	// Get our Tailscale IP
+	lc, err := s.LocalClient()
+	if err != nil {
+		log.Fatalf("local client: %v", err)
+	}
+	st, err := lc.Status(context.Background())
+	if err != nil {
+		log.Fatalf("status: %v", err)
+	}
+	log.Printf("[1/4] Connected to tailnet. Our IP: %v", st.Self.TailscaleIPs)
+
+	// Step 2: Start local proxy
+	log.Println("[2/4] Starting local proxy...")
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		log.Fatalf("listen: %v", err)
+	}
+	defer ln.Close()
+
+	localPort := ln.Addr().(*net.TCPAddr).Port
+	remoteAddr := fmt.Sprintf("%s:%d", *heaterIP, *heaterPort)
+	log.Printf("[2/4] Proxy: 127.0.0.1:%d → %s (via Tailscale)", localPort, remoteAddr)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// Accept one connection for the test
+	go func() {
+		conn, err := ln.Accept()
+		if err != nil {
+			return
+		}
+		defer conn.Close()
+
+		remote, err := s.Dial(ctx, "tcp", remoteAddr)
+		if err != nil {
+			log.Printf("[PROXY] Dial failed: %v", err)
+			return
+		}
+		defer remote.Close()
+
+		done := make(chan struct{}, 2)
+		go func() { io.Copy(remote, conn); done <- struct{}{} }()
+		go func() { io.Copy(conn, remote); done <- struct{}{} }()
+		<-done
+	}()
+
+	// Step 3: Connect through the proxy
+	log.Println("[3/4] Testing TCP connection through proxy...")
+	conn, err := net.DialTimeout("tcp", fmt.Sprintf("127.0.0.1:%d", localPort), 10*time.Second)
+	if err != nil {
+		log.Fatalf("FAIL — could not connect through proxy: %v", err)
+	}
+	defer conn.Close()
+
+	// For gRPC/HTTP2, we can just check that the TCP connection succeeds
+	// and the remote end responds (gRPC sends a settings frame)
+	conn.SetReadDeadline(time.Now().Add(5 * time.Second))
+	buf := make([]byte, 64)
+	n, err := conn.Read(buf)
+	if err != nil && err != io.EOF {
+		// Timeout is OK — gRPC server waits for client to send first
+		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
+			log.Println("[3/4] TCP connection established (gRPC server awaiting client preface)")
+		} else {
+			log.Printf("[3/4] Read response: %v (this may be OK for gRPC)", err)
+		}
+	} else {
+		log.Printf("[3/4] Received %d bytes from heater", n)
+	}
+
+	// Step 4: Result
+	log.Println("[4/4] SUCCESS — Tailscale tunnel is working!")
+	log.Printf("")
+	log.Printf("  Heater reachable at %s via Tailscale", remoteAddr)
+	log.Printf("  Local proxy: 127.0.0.1:%d", localPort)
+	log.Printf("")
+	log.Printf("  Next: use this in the Flutter app:")
+	log.Printf("    await tailscaleKit.start(authKey: '%s');", *authKey)
+	log.Printf("    final port = await tailscaleKit.startProxy('%s');", *heaterIP)
+	log.Printf("    grpcService.connect('127.0.0.1', port: port);")
+}