HdmiCecMessageValidator.java revision 75a77e7d6cbfc287c6126efd28b338b48b7ea70c 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.server.hdmi;
18
19import android.hardware.hdmi.HdmiCecDeviceInfo;
20import android.util.Slog;
21import android.util.SparseArray;
22
23/**
24 * A helper class to validates {@link HdmiCecMessage}.
25 */
26public final class HdmiCecMessageValidator {
27    private static final String TAG = "HdmiCecMessageValidator";
28
29    private final HdmiControlService mService;
30
31    interface ParameterValidator {
32        boolean isValid(byte[] params);
33    }
34
35    final SparseArray<ParameterValidator> mValidators = new SparseArray<>();
36
37    public HdmiCecMessageValidator(HdmiControlService service) {
38        mService = service;
39
40        // Messages related to the physical address.
41        PhysicalAddressValidator physicalAddressValidator = new PhysicalAddressValidator();
42        mValidators.append(Constants.MESSAGE_ACTIVE_SOURCE, physicalAddressValidator);
43        mValidators.append(Constants.MESSAGE_INACTIVE_SOURCE, physicalAddressValidator);
44        mValidators.append(Constants.MESSAGE_REPORT_PHYSICAL_ADDRESS,
45                new ReportPhysicalAddressValidator());
46        mValidators.append(Constants.MESSAGE_ROUTING_CHANGE, new RoutingChangeValidator());
47        mValidators.append(Constants.MESSAGE_ROUTING_INFORMATION, physicalAddressValidator);
48        mValidators.append(Constants.MESSAGE_SET_STREAM_PATH, physicalAddressValidator);
49        mValidators.append(Constants.MESSAGE_SYSTEM_AUDIO_MODE_REQUEST, physicalAddressValidator);
50
51        // Messages have no parameter.
52        FixedLengthValidator noneValidator = new FixedLengthValidator(0);
53        mValidators.append(Constants.MESSAGE_ABORT, noneValidator);
54        mValidators.append(Constants.MESSAGE_GET_CEC_VERSION, noneValidator);
55        mValidators.append(Constants.MESSAGE_GET_MENU_LANGUAGE, noneValidator);
56        mValidators.append(Constants.MESSAGE_GIVE_AUDIO_STATUS, noneValidator);
57        mValidators.append(Constants.MESSAGE_GIVE_DEVICE_POWER_STATUS, noneValidator);
58        mValidators.append(Constants.MESSAGE_GIVE_DEVICE_VENDOR_ID, noneValidator);
59        mValidators.append(Constants.MESSAGE_GIVE_OSD_NAME, noneValidator);
60        mValidators.append(Constants.MESSAGE_GIVE_PHYSICAL_ADDRESS, noneValidator);
61        mValidators.append(Constants.MESSAGE_GIVE_SYSTEM_AUDIO_MODE_STATUS, noneValidator);
62        mValidators.append(Constants.MESSAGE_IMAGE_VIEW_ON, noneValidator);
63        mValidators.append(Constants.MESSAGE_INITIATE_ARC, noneValidator);
64        mValidators.append(Constants.MESSAGE_RECORD_OFF, noneValidator);
65        mValidators.append(Constants.MESSAGE_RECORD_TV_SCREEN, noneValidator);
66        mValidators.append(Constants.MESSAGE_REPORT_ARC_INITIATED, noneValidator);
67        mValidators.append(Constants.MESSAGE_REPORT_ARC_TERMINATED, noneValidator);
68        mValidators.append(Constants.MESSAGE_REQUEST_ARC_INITIATION, noneValidator);
69        mValidators.append(Constants.MESSAGE_REQUEST_ARC_TERMINATION, noneValidator);
70        mValidators.append(Constants.MESSAGE_REQUEST_ACTIVE_SOURCE, noneValidator);
71        mValidators.append(Constants.MESSAGE_STANDBY, noneValidator);
72        mValidators.append(Constants.MESSAGE_TERMINATE_ARC, noneValidator);
73        mValidators.append(Constants.MESSAGE_TEXT_VIEW_ON, noneValidator);
74        mValidators.append(Constants.MESSAGE_TUNER_STEP_DECREMENT, noneValidator);
75        mValidators.append(Constants.MESSAGE_TUNER_STEP_INCREMENT, noneValidator);
76        mValidators.append(Constants.MESSAGE_USER_CONTROL_RELEASED, noneValidator);
77        mValidators.append(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_UP, noneValidator);
78
79        // TODO: Validate more than length for the following messages.
80
81        // Messages for the One Touch Record.
82        FixedLengthValidator oneByteValidator = new FixedLengthValidator(1);
83        mValidators.append(Constants.MESSAGE_RECORD_ON, new VariableLengthValidator(1, 8));
84        mValidators.append(Constants.MESSAGE_RECORD_STATUS, oneByteValidator);
85
86        // TODO: Handle messages for the Timer Programming.
87
88        // Messages for the System Information.
89        mValidators.append(Constants.MESSAGE_CEC_VERSION, oneByteValidator);
90        mValidators.append(Constants.MESSAGE_SET_MENU_LANGUAGE, new FixedLengthValidator(3));
91
92        // TODO: Handle messages for the Deck Control.
93
94        // TODO: Handle messages for the Tuner Control.
95
96        // Messages for the Vendor Specific Commands.
97        VariableLengthValidator maxLengthValidator = new VariableLengthValidator(0, 14);
98        mValidators.append(Constants.MESSAGE_DEVICE_VENDOR_ID, new FixedLengthValidator(3));
99        mValidators.append(Constants.MESSAGE_VENDOR_COMMAND, maxLengthValidator);
100        mValidators.append(Constants.MESSAGE_VENDOR_COMMAND_WITH_ID, maxLengthValidator);
101        mValidators.append(Constants.MESSAGE_VENDOR_REMOTE_BUTTON_DOWN, maxLengthValidator);
102
103        // Messages for the OSD.
104        mValidators.append(Constants.MESSAGE_SET_OSD_STRING, maxLengthValidator);
105        mValidators.append(Constants.MESSAGE_SET_OSD_NAME, maxLengthValidator);
106
107        // TODO: Handle messages for the Device Menu Control.
108
109        // Messages for the Remote Control Passthrough.
110        // TODO: Parse the first parameter and determine if it can have the next parameter.
111        mValidators.append(Constants.MESSAGE_USER_CONTROL_PRESSED,
112                new VariableLengthValidator(1, 2));
113
114        // Messages for the Power Status.
115        mValidators.append(Constants.MESSAGE_REPORT_POWER_STATUS, oneByteValidator);
116
117        // Messages for the General Protocol.
118        mValidators.append(Constants.MESSAGE_FEATURE_ABORT, new FixedLengthValidator(2));
119
120        // Messages for the System Audio Control.
121        mValidators.append(Constants.MESSAGE_REPORT_AUDIO_STATUS, oneByteValidator);
122        mValidators.append(Constants.MESSAGE_REPORT_SHORT_AUDIO_DESCRIPTOR,
123                new FixedLengthValidator(3));
124        mValidators.append(Constants.MESSAGE_REQUEST_SHORT_AUDIO_DESCRIPTOR, oneByteValidator);
125        mValidators.append(Constants.MESSAGE_SET_SYSTEM_AUDIO_MODE, oneByteValidator);
126        mValidators.append(Constants.MESSAGE_SYSTEM_AUDIO_MODE_STATUS, oneByteValidator);
127
128        // Messages for the Audio Rate Control.
129        mValidators.append(Constants.MESSAGE_SET_AUDIO_RATE, oneByteValidator);
130
131        // All Messages for the ARC have no parameters.
132
133        // Messages for the Capability Discovery and Control.
134        mValidators.append(Constants.MESSAGE_CDC_MESSAGE, maxLengthValidator);
135    }
136
137    boolean isValid(HdmiCecMessage message) {
138        int opcode = message.getOpcode();
139        ParameterValidator validator = mValidators.get(opcode);
140        if (validator == null) {
141            Slog.i(TAG, "No validator for the message: " + message);
142            return true;
143        }
144        return validator.isValid(message.getParams());
145    }
146
147    private static class FixedLengthValidator implements ParameterValidator {
148        private final int mLength;
149
150        public FixedLengthValidator(int length) {
151            mLength = length;
152        }
153
154        @Override
155        public boolean isValid(byte[] params) {
156            return params.length == mLength;
157        }
158    }
159
160    private static class VariableLengthValidator implements ParameterValidator {
161        private final int mMinLength;
162        private final int mMaxLength;
163
164        public VariableLengthValidator(int minLength, int maxLength) {
165            mMinLength = minLength;
166            mMaxLength = maxLength;
167        }
168
169        @Override
170        public boolean isValid(byte[] params) {
171            return params.length >= mMinLength && params.length <= mMaxLength;
172        }
173    }
174
175    private boolean isValidPhysicalAddress(byte[] params, int offset) {
176        int path = HdmiUtils.twoBytesToInt(params, offset);
177        int portId = mService.pathToPortId(path);
178        if (portId == Constants.INVALID_PORT_ID) {
179            return false;
180        }
181        // TODO: Add more logic like validating 1.0.1.0.
182        return true;
183    }
184
185    /**
186     * Check if the given type is valid. A valid type is one of the actual
187     * logical device types defined in the standard ({@link #DEVICE_TV},
188     * {@link #DEVICE_PLAYBACK}, {@link #DEVICE_TUNER}, {@link #DEVICE_RECORDER},
189     * and {@link #DEVICE_AUDIO_SYSTEM}).
190     *
191     * @param type device type
192     * @return true if the given type is valid
193     */
194    static boolean isValidType(int type) {
195        return (HdmiCecDeviceInfo.DEVICE_TV <= type
196                && type <= HdmiCecDeviceInfo.DEVICE_VIDEO_PROCESSOR)
197                && type != HdmiCecDeviceInfo.DEVICE_RESERVED;
198    }
199
200    private class PhysicalAddressValidator implements ParameterValidator {
201        @Override
202        public boolean isValid(byte[] params) {
203            if (params.length != 2) {
204                return false;
205            }
206            return isValidPhysicalAddress(params, 0);
207        }
208    }
209
210    private class ReportPhysicalAddressValidator implements ParameterValidator {
211        @Override
212        public boolean isValid(byte[] params) {
213            if (params.length != 3) {
214                return false;
215            }
216            return isValidPhysicalAddress(params, 0) && isValidType(params[2]);
217        }
218    }
219
220    private class RoutingChangeValidator implements ParameterValidator {
221        @Override
222        public boolean isValid(byte[] params) {
223            if (params.length != 4) {
224                return false;
225            }
226            return isValidPhysicalAddress(params, 0) && isValidPhysicalAddress(params, 2);
227        }
228    }
229}
230