feat(ios): native usbmux client and in-process tunnel forwarder

Talk to macOS usbmuxd directly instead of shelling out to iproxy, so the
device path depends on nothing beyond macOS + Xcode.

internal/driver/ioscompanion/usbmux_test.go

@@ -0,0 +1,228 @@
+package ioscompanion
+
+import (
+	"context"
+	"io"
+	"net"
+	"testing"
+)
+
+func TestHtonsSwapsBytes(t *testing.T) {
+	// 49200 = 0xC030; network order swaps to 0x30C0 = 12480.
+	if got := htons(49200); got != 12480 {
+		t.Fatalf("htons(49200) = %d, want 12480", got)
+	}
+	if got := htons(0x1234); got != 0x3412 {
+		t.Fatalf("htons(0x1234) = %#x, want 0x3412", got)
+	}
+}
+
+func TestEncodePlistDictRoundTrips(t *testing.T) {
+	encoded, err := encodePlistDict(map[string]any{
+		"MessageType": "Connect",
+		"DeviceID":    7,
+		"PortNumber":  12480,
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	dict, err := parsePlistDict(encoded)
+	if err != nil {
+		t.Fatalf("parse round-trip: %v", err)
+	}
+	if dict["MessageType"] != "Connect" {
+		t.Fatalf("MessageType = %v, want Connect", dict["MessageType"])
+	}
+	if dict["DeviceID"] != 7 {
+		t.Fatalf("DeviceID = %v, want 7", dict["DeviceID"])
+	}
+	if dict["PortNumber"] != 12480 {
+		t.Fatalf("PortNumber = %v, want 12480", dict["PortNumber"])
+	}
+}
+
+func TestEncodePlistDictEscapesStrings(t *testing.T) {
+	encoded, err := encodePlistDict(map[string]any{"Name": "a & b <c>"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	dict, err := parsePlistDict(encoded)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if dict["Name"] != "a & b <c>" {
+		t.Fatalf("Name = %q, want the unescaped original", dict["Name"])
+	}
+}
+
+// listDevicesReply is a representative usbmux ListDevices response with one USB
+// device, matching the shape macOS usbmuxd returns.
+const listDevicesReply = `<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>DeviceList</key>
+  <array>
+    <dict>
+      <key>DeviceID</key>
+      <integer>7</integer>
+      <key>MessageType</key>
+      <string>Attached</string>
+      <key>Properties</key>
+      <dict>
+        <key>ConnectionType</key>
+        <string>USB</string>
+        <key>SerialNumber</key>
+        <string>00008140-00022C4A3E13001C</string>
+      </dict>
+    </dict>
+  </array>
+</dict>
+</plist>`
+
+func TestSelectDeviceIDMatchesDashedSerial(t *testing.T) {
+	list, err := parsePlistDict([]byte(listDevicesReply))
+	if err != nil {
+		t.Fatal(err)
+	}
+	id, err := selectDeviceID(list, "00008140-00022C4A3E13001C")
+	if err != nil {
+		t.Fatalf("select by dashed serial: %v", err)
+	}
+	if id != 7 {
+		t.Fatalf("DeviceID = %d, want 7", id)
+	}
+}
+
+func TestSelectDeviceIDMatchesUndashedSerial(t *testing.T) {
+	list, err := parsePlistDict([]byte(listDevicesReply))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// The raw USB serial carries no dash; it must still resolve.
+	id, err := selectDeviceID(list, "0000814000022C4A3E13001C")
+	if err != nil {
+		t.Fatalf("select by undashed serial: %v", err)
+	}
+	if id != 7 {
+		t.Fatalf("DeviceID = %d, want 7", id)
+	}
+}
+
+func TestSelectDeviceIDNotAttached(t *testing.T) {
+	list, err := parsePlistDict([]byte(listDevicesReply))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := selectDeviceID(list, "DEADBEEF-NOTHERE"); err == nil {
+		t.Fatal("a serial not in the list must error")
+	}
+}
+
+func TestParsePlistDictRejectsNonDictRoot(t *testing.T) {
+	arrayRoot := `<?xml version="1.0"?><plist version="1.0"><array></array></plist>`
+	if _, err := parsePlistDict([]byte(arrayRoot)); err == nil {
+		t.Fatal("a non-dict plist root must error")
+	}
+}
+
+// TestForwarderBridgesToDevice drives the forwarder end to end against an
+// in-process echo "device": a host connection through the loopback listener must
+// reach the injected device dialer and round-trip bytes.
+func TestForwarderBridgesToDevice(t *testing.T) {
+	deviceListener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer deviceListener.Close()
+	go func() {
+		for {
+			conn, acceptErr := deviceListener.Accept()
+			if acceptErr != nil {
+				return
+			}
+			go io.Copy(conn, conn)
+		}
+	}()
+
+	localAddress, err := pickLoopbackAddress()
+	if err != nil {
+		t.Fatal(err)
+	}
+	forwarder, err := startForwarder(context.Background(), localAddress, func(ctx context.Context) (net.Conn, error) {
+		return net.Dial("tcp", deviceListener.Addr().String())
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer forwarder.Close()
+
+	hostConn, err := net.Dial("tcp", localAddress)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer hostConn.Close()
+
+	message := []byte("ping\n")
+	if _, err := hostConn.Write(message); err != nil {
+		t.Fatal(err)
+	}
+	buffer := make([]byte, len(message))
+	if _, err := io.ReadFull(hostConn, buffer); err != nil {
+		t.Fatal(err)
+	}
+	if string(buffer) != string(message) {
+		t.Fatalf("round-trip = %q, want %q", buffer, message)
+	}
+}
+
+// TestForwarderClosesHostOnDeviceDialFailure asserts the failure path the runner
+// transport relies on: when the device dial fails (the runner not yet
+// listening), the forwarder closes the host side so the caller sees a dropped
+// connection and retries.
+func TestForwarderClosesHostOnDeviceDialFailure(t *testing.T) {
+	localAddress, err := pickLoopbackAddress()
+	if err != nil {
+		t.Fatal(err)
+	}
+	forwarder, err := startForwarder(context.Background(), localAddress, func(ctx context.Context) (net.Conn, error) {
+		return nil, io.ErrUnexpectedEOF
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer forwarder.Close()
+
+	hostConn, err := net.Dial("tcp", localAddress)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer hostConn.Close()
+
+	// The forwarder closes its side after the failed device dial; the read
+	// returns EOF rather than blocking forever.
+	if _, err := io.ReadFull(hostConn, make([]byte, 1)); err == nil {
+		t.Fatal("read must fail once the forwarder closes the host side")
+	}
+}
+
+func TestForwarderCloseStopsAcceptLoop(t *testing.T) {
+	localAddress, err := pickLoopbackAddress()
+	if err != nil {
+		t.Fatal(err)
+	}
+	forwarder, err := startForwarder(context.Background(), localAddress, func(ctx context.Context) (net.Conn, error) {
+		return nil, io.EOF
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := forwarder.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// After Close the listener is gone, so a dial must fail.
+	if conn, dialErr := net.Dial("tcp", localAddress); dialErr == nil {
+		conn.Close()
+		t.Fatal("dial must fail after the forwarder is closed")
+	}
+}