TUN-6531: Implement ICMP proxy for Windows using IcmpSendEcho

ingress/icmp_windows_test.go

@@ -0,0 +1,139 @@
+//go:build windows
+
+package ingress
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"net/netip"
+	"testing"
+	"unsafe"
+
+	"golang.org/x/net/icmp"
+
+	"github.com/stretchr/testify/require"
+)
+
+// TestParseEchoReply tests parsing raw bytes from icmpSendEcho into echoResp
+func TestParseEchoReply(t *testing.T) {
+	dst, err := inAddrV4(netip.MustParseAddr("192.168.10.20"))
+	require.NoError(t, err)
+
+	validReplyData := []byte(t.Name())
+	validReply := echoReply{
+		Address:       dst,
+		Status:        success,
+		RoundTripTime: uint32(20),
+		DataSize:      uint16(len(validReplyData)),
+		DataPointer:   &validReplyData[0],
+		Options: ipOption{
+			TTL: 59,
+		},
+	}
+
+	destHostUnreachableReply := validReply
+	destHostUnreachableReply.Status = destHostUnreachable
+
+	tests := []struct {
+		testCase      string
+		replyBuf      []byte
+		expectedReply *echoReply
+		expectedData  []byte
+	}{
+		{
+			testCase: "empty buffer",
+		},
+		{
+			testCase: "status not success",
+			replyBuf: destHostUnreachableReply.marshal(t, []byte{}),
+		},
+		{
+			testCase:      "valid reply",
+			replyBuf:      validReply.marshal(t, validReplyData),
+			expectedReply: &validReply,
+			expectedData:  validReplyData,
+		},
+	}
+
+	for _, test := range tests {
+		resp, err := newEchoResp(test.replyBuf)
+		if test.expectedReply == nil {
+			require.Error(t, err)
+			require.Nil(t, resp)
+		} else {
+			require.NoError(t, err)
+			require.Equal(t, resp.reply, test.expectedReply)
+			require.True(t, bytes.Equal(resp.data, test.expectedData))
+		}
+	}
+}
+
+//  TestSendEchoErrors makes sure icmpSendEcho handles error cases
+func TestSendEchoErrors(t *testing.T) {
+	proxy, err := newICMPProxy(localhostIP, &noopLogger)
+	require.NoError(t, err)
+	winProxy := proxy.(*icmpProxy)
+
+	echo := icmp.Echo{
+		ID:   6193,
+		Seq:  25712,
+		Data: []byte(t.Name()),
+	}
+	documentIP := netip.MustParseAddr("192.0.2.200")
+	resp, err := winProxy.icmpSendEcho(documentIP, &echo)
+	require.Error(t, err)
+	require.Nil(t, resp)
+}
+
+func (er *echoReply) marshal(t *testing.T, data []byte) []byte {
+	buf := new(bytes.Buffer)
+
+	for _, field := range []any{
+		er.Address,
+		er.Status,
+		er.RoundTripTime,
+		er.DataSize,
+		er.Reserved,
+	} {
+		require.NoError(t, binary.Write(buf, endian, field))
+	}
+
+	require.NoError(t, marshalPointer(buf, uintptr(unsafe.Pointer(er.DataPointer))))
+
+	for _, field := range []any{
+		er.Options.TTL,
+		er.Options.Tos,
+		er.Options.Flags,
+		er.Options.OptionsSize,
+	} {
+		require.NoError(t, binary.Write(buf, endian, field))
+	}
+
+	require.NoError(t, marshalPointer(buf, er.Options.OptionsData))
+
+	padSize := buf.Len() % int(unsafe.Alignof(er))
+	padding := make([]byte, padSize)
+	n, err := buf.Write(padding)
+	require.NoError(t, err)
+	require.Equal(t, padSize, n)
+
+	n, err = buf.Write(data)
+	require.NoError(t, err)
+	require.Equal(t, len(data), n)
+
+	return buf.Bytes()
+}
+
+func marshalPointer(buf io.Writer, ptr uintptr) error {
+	size := unsafe.Sizeof(ptr)
+	switch size {
+	case 4:
+		return binary.Write(buf, endian, uint32(ptr))
+	case 8:
+		return binary.Write(buf, endian, uint64(ptr))
+	default:
+		return fmt.Errorf("unexpected pointer size %d", size)
+	}
+}