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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.nfc;
import android.content.Context;
import android.content.Intent;
import android.net.wifi.WifiConfiguration;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.tech.Ndef;
import android.os.UserHandle;
import android.os.UserManager;
import android.util.Log;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.BitSet;
public final class NfcWifiProtectedSetup {
public static final String NFC_TOKEN_MIME_TYPE = "application/vnd.wfa.wsc";
public static final String EXTRA_WIFI_CONFIG = "com.android.nfc.WIFI_CONFIG_EXTRA";
/*
* ID into configuration record for SSID and Network Key in hex.
* Obtained from WFA Wifi Simple Configuration Technical Specification v2.0.2.1.
*/
private static final short CREDENTIAL_FIELD_ID = 0x100E;
private static final short SSID_FIELD_ID = 0x1045;
private static final short NETWORK_KEY_FIELD_ID = 0x1027;
private static final short AUTH_TYPE_FIELD_ID = 0x1003;
private static final short AUTH_TYPE_EXPECTED_SIZE = 2;
private static final short AUTH_TYPE_OPEN = 0;
private static final short AUTH_TYPE_WPA_PSK = 0x0002;
private static final short AUTH_TYPE_WPA_EAP = 0x0008;
private static final short AUTH_TYPE_WPA2_EAP = 0x0010;
private static final short AUTH_TYPE_WPA2_PSK = 0x0020;
private static final int MAX_NETWORK_KEY_SIZE_BYTES = 64;
private NfcWifiProtectedSetup() {}
public static boolean tryNfcWifiSetup(Ndef ndef, Context context) {
if (ndef == null || context == null) {
return false;
}
NdefMessage cachedNdefMessage = ndef.getCachedNdefMessage();
if (cachedNdefMessage == null) {
return false;
}
final WifiConfiguration wifiConfiguration;
try {
wifiConfiguration = parse(cachedNdefMessage);
} catch (BufferUnderflowException e) {
// malformed payload
return false;
}
if (wifiConfiguration != null &&!UserManager.get(context).hasUserRestriction(
UserManager.DISALLOW_CONFIG_WIFI, UserHandle.CURRENT)) {
Intent configureNetworkIntent = new Intent()
.putExtra(EXTRA_WIFI_CONFIG, wifiConfiguration)
.setClass(context, ConfirmConnectToWifiNetworkActivity.class)
.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivityAsUser(configureNetworkIntent, UserHandle.CURRENT);
return true;
}
return false;
}
private static WifiConfiguration parse(NdefMessage message) {
NdefRecord[] records = message.getRecords();
for (NdefRecord record : records) {
if (new String(record.getType()).equals(NFC_TOKEN_MIME_TYPE)) {
ByteBuffer payload = ByteBuffer.wrap(record.getPayload());
while (payload.hasRemaining()) {
short fieldId = payload.getShort();
short fieldSize = payload.getShort();
if (fieldId == CREDENTIAL_FIELD_ID) {
return parseCredential(payload, fieldSize);
}
}
}
}
return null;
}
private static WifiConfiguration parseCredential(ByteBuffer payload, short size) {
int startPosition = payload.position();
WifiConfiguration result = new WifiConfiguration();
while (payload.position() < startPosition + size) {
short fieldId = payload.getShort();
short fieldSize = payload.getShort();
// sanity check
if (payload.position() + fieldSize > startPosition + size) {
return null;
}
switch (fieldId) {
case SSID_FIELD_ID:
byte[] ssid = new byte[fieldSize];
payload.get(ssid);
result.SSID = "\"" + new String(ssid) + "\"";
break;
case NETWORK_KEY_FIELD_ID:
if (fieldSize > MAX_NETWORK_KEY_SIZE_BYTES) {
return null;
}
byte[] networkKey = new byte[fieldSize];
payload.get(networkKey);
result.preSharedKey = "\"" + new String(networkKey) + "\"";
break;
case AUTH_TYPE_FIELD_ID:
if (fieldSize != AUTH_TYPE_EXPECTED_SIZE) {
// corrupt data
return null;
}
short authType = payload.getShort();
populateAllowedKeyManagement(result.allowedKeyManagement, authType);
break;
default:
// unknown / unparsed tag
payload.position(payload.position() + fieldSize);
break;
}
}
if (result.preSharedKey != null && result.SSID != null) {
return result;
}
return null;
}
private static void populateAllowedKeyManagement(BitSet allowedKeyManagement, short authType) {
if (authType == AUTH_TYPE_WPA_PSK || authType == AUTH_TYPE_WPA2_PSK) {
allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
} else if (authType == AUTH_TYPE_WPA_EAP || authType == AUTH_TYPE_WPA2_EAP) {
allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP);
} else if (authType == AUTH_TYPE_OPEN) {
allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
}
}
}
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