Using wifi

This is not about packet formats and other aspects of 802.11, but only how to

use wifi on the Android platform

Wifi modes• A 802.11 node can be in one of the following modes

– Access point (AP) infrastructure mode• Your linksys “router” at home is an AP.

– It is not a router (it does not exchange routing messages with other routers), but is an AP and a NAT

• A linux box can be an AP by using hostpad• An Android phone can also be AP

– Station infrastructure mode• When you connect your laptop to an AP, your laptop is in station infrastructure mode.

– Monitor mode• Promiscuous mode is able to receive frames even if the frame destination MAC address is not this node• This is useful to

– spy on networks (bad)– Debugging network (good)– Smart/cognitive wifi (good)

» E.g., the node receives frames from other nodes and can determine if other nodes provide a better path» A node receives other frames and determines that the channel is too busy and adjusts, for example, audio compression» Etc.

– Maybe chips can sleep once they determine that the frame is not destined for this node. This can save power. However, this requires the node not be in monitor node

• Monitor mode is not supported in nexus one or nexus s wifi chips• Some chips can be in station mode and monitor mode at the same time

– Ad hoc mode• Nodes can communicate with each other without an AP• This allows peer-to-peer communication, however, it is not wifi-direct• Android does not support ad hoc mode, but a rooted phone can be made to support ad hoc

– Wifi-direct• New protocol that allows nodes to communicate directly without an AP• Nodes that use wifi-direct can also simultaneously communicate with an AP (ad mode cannot do this)• There are hints that furture android APIs will support wifi direct• Some phones already have wifi direct• Also known as wifi p2p (this is the name used by the driver developers)

– Mesh• Allows nodes to act as routes and access points. • Not widely supported• Not supported by mobile phones

wpa_supplicant

• Running wifi– Let android system help

• Manually starting on nexus S– Do the following while having root privileges – Load wifi driver

• on nexus S– insmod /system/modules/bcm4329.ko

• On nexus one– -insmod /system/lib/modules/bcm4329.ko (not sure if this works)

• On others, look for driver with find . –name *.ko

– Check that driver loaded• lsmod• Should show driver is running

– Start wifi• /system/bin/wpa_supplicant –Dext –ieth0 –c/data/misc/wifi_wpa_supplicant.conf

– Run dhcp• /system/bin/dhcpcd –c/system/etc/dhcpcd/dhcpcd.conf –b eth0 (does not work)

Wifi hardware

Wifi driver

wpa_supplicant

Android system Your app

wpa_supplicant.conf

wpa_supplicant.conf• See examples and information at

– http://user.uni-frankfurt.de/~testrad/wpa_supplicant/wpa_supplicant.conf.examples• See /data/misc/wifi/wpa-supplicant.conf

– ctrl_interface=eth0– update_config=1

– Network={• ssid=“something”• psk=“something”• key_mgmt=WPA-PSK• priority=1• }

– More of the same• Note, passwords are stored in the .cof file, so this file can only be accessed via root privileges

• Update_config=1 allows the conf to be overwritten when updated, e.g., when a new network is added• ctrl_interface

– Interaction with the wpa_supplicant is through “unix sockets.” – The location of this socket is given by the argument to ctrl_interface=. However, eth0 does not really make sense– When wiif is running, see ls /data/misc/wifi/sockets to see the unix sockets

• ap_scan– While not given in the example above, ap_scan can be used– ap_scan=1

• Allows the wpa_supplicant to initiate scaning and ap selection by using the wpa_supplicant.conf• This is the default

– ap_scan=0• The driver scans for Aps, and associates with the AP• This mode is best if the driver does not good wpa_supplicant support

– ap_scan=2• Not always supported• Does no scan, just asks driver to connect• This will allow connections to ad hoc networks

• Network block– ssid=“something”

• Sets the ssid of the ap– scan_ssid

• =0– Do not scan

• =1– Scan with ssid-specific probe request. – This is used to find Aps that do not broadcast ssid

– Priority• High numbers means attemp to connect to this network first• Not used when ap_scan=2. in this case, the order that networks appear is used

– Mode• =0 inferstructure• =1 IBSS or ad hoc

– Requires key_mgmt = NONE or key_mgmt=WPA-NONE

Ad hoc

• The wpa_supplicant.conf must be changed• ap_scan=2• Network = {– ssid = “MyAdHocNetwork”– mode = 1– key_mgmt = NONE– }

• Other networks…– These networks will likely not be used

IP address• If ap_scan=2 and dhcp is used

– Connection is attempted to each network in the order they appear– If the network is an infrastructure, then

• an association is attempted. • if associate fails, then the a connection to the next network is the list is attempted

– If the network is ad hoc, • then dhcp is attempted.• If dhcp fails, then a connection with the next network in the list is attempted

– This step is initiated by the android system, not the wpa_supplicant+wifi-driver system

• If ap_scan=2 and the ip address is set statically,– Connection is attempted to each network in the order they appear– If the network is an infrastructure, then

• an association is attempted. • if associate fails, then the a connection to the next network is the list is attempted

– If the network is ad hoc, • Then the static ip is used, and the connection is complete

• Conclusions– Assuming that dhcp is not available in the ad hoc network, using a static IP is required for ad hoc, and not setting the ip address will

essentially disable the ad hoc mode• That is, if the wpa_supplicant can remain fixed, with ap_scan=2 and ad hoc mode can be enabled by setting a static ip

– However, when ad hoc mode is not used (i.e., the ip is not set to be a static ip), then association with a network is delayed by the dhcp attempt on the ad hoc network• This makes the performance a bit sluggish when are connecting to a network

– Therefore, the best performance is achieved by using a different wpa_supplicant.conf depending on whether ad hoc mode is to be used.• Just to be safe, we only change the ap_scan=1 or 2 in the wpa_supplicant.conf. That way, the wpa_supplicant.conf will always be able to connect to

access points as usual

Connecting to ad hoc network

• Initial set up– Make sure that ap_scan=1 conf file includes all networks that are in ap_scan=2 .conf file– Check that conf file with ap_scan=1 is backed up– make sure all conf files are only accessible with root privilege

• Turn on ad hoc– Copy conf file with ap_scan = 2 to

• /data/misc/wifi/wpa_supplicant.conf

– Set permissions of wpa_supplicant.conf– Set owner of wpa_supplicant.conf

• Otherwise, when the system reboots, the permission of the wpa_supplicant is incorrectly set

– Stop wifi– When wifi is stopped, set static ip– Start wifi

• Turn off– Copy conf file with ap_scan = 1 to

• /data/misc/wifi/wpa_suplicant.conf

– Set permisions of wpa_supplicant.conf– Set owner of wpa_supplicant.conf– Stop wifi– Once stopped

• Disable static ip

– Start wifi

wpa_supplicant.conf permissions

• The conf contains password for access points, and therefore requires super-user privilege to access– On a rooted phone will allow any app get access to

AP passwords!• Also, the wpa_supplicant.conf must be owned

by the wifi system, otherwise, after boot up, the permissions would be incorrect

Ad hoc mode does not work

• Sometime ad hoc mode does not work– This might be a bug in the android wifi system, or

maybe a parameter is set incorrectly• Rebooting often fixes the problem

To do• Set IP address • wpa_supplicant.conf stuff

– Save current .conf– ap_scan

• =2 if we want ad hoc mode• =1 if we want to connect to an access point

– Save and set permissions• Set ad hoc mode

– Turn off wifi– Wait until it is off– Change settings– Turn on– Check if succeeded

• We can only check after a little while, so we need to set a timer (use Handler class)• Call callback function when finished

– If failed, then try rebooting the phone» ((PowerManager) getSystemService(Context.POWER_SERVICE)).reboot(); // requires reboot permission

• Needs– Permissions

• ACCESS_WIFI_STATE• ACCESS_NETWORK_STATE• CHANGE_WIFI_STATE• WRITE_SETTINGS

– Root access– cp command in /system/xbin

• This can be installed by installing busy box

AdHocConnectionManager• Is the main class for controlling ad hoc connections• Contrustor is AdHocConnectionManager(Context _context, String _baseDirPath, TextView

_statusView)– The textview, can be null, or can be a textVeiw object where the wifi state will be written

• Public functions– public void startAdHoc(String _ssidOfAdHocNetwork, WifiConnectionResponse _responseObject)

• Calls callback when the conenction succeeds or fails• Note, the connection to ad hoc does not occur until several seconds after this function is called

– Public void stopAdHoc()• Disables ad hoc and returns wpa_supplicant.conf to original state

– public String getWifStatus()• Returns a string that includes the current state of the wifi

– public void showWifiStatus()• Shows the wiif status in the log

– public void turnWifiOn()– public void turnWifiOff()– public boolean connectedToDesiredAdHocNetwork()

• Returns true if connected To Desired Ad Hoc Network

example• From class web page get classes

–WpaSupplicantConfManager– IPAddressManager– AdHocConnectionManager– Note, more details on these classes is on the following slides

• Make new app called TurnOnAdHocTest• Go to layout and

– Add buttons• StartAdHoc• StopAdHoc• ShowStatus• TurnWifiOn• TurnWifiOff

– Add TextView, called textView

• Add member variables– TextView textView = null;– AdHocConnectionManager adHocConnectionManager;

• In onCreate, after setContentView, add– textView = (TextView)findViewById(R.id.Status);– adHocConnectionManager = new AdHocConnectionManager(this,

this.getFilesDir().getAbsolutePath(), textView);

– Button startAdHocButton = (Button)findViewById(R.id.startAdHoc);– startAdHocButton.setOnClickListener(new View.OnClickListener() {• @Override• public void onClick(View v) {• Log.e("TurnOnWifi","clicked start ad hoc");• adHocConnectionManager.startAdHoc("MyAdHoc", new

AdHocConnectionManager.WifiConnectionResponse(){– @Override– public void response(boolean connectionSucceeded) {

» if (connectionSucceeded) {• Log.e("debug","Connected to ad hoc network");

» } else {• Log.e("debug","Failed to connected to ad hoc network");

» }• }});

– }});

• Button stopAdHocButton = (Button)findViewById(R.id.stopAdHoc);• stopAdHocButton.setOnClickListener(new

View.OnClickListener() {– @Override– public void onClick(View v) {• adHocConnectionManager.stopAdHoc();

– }});

• Button showWifi = (Button)findViewById(R.id.showWifiState);• showWifi.setOnClickListener(new View.OnClickListener() {– @Override– public void onClick(View v) {• Log.e("wifi status",adHocConnectionManager.getWifStatus());

– }});

• Button wifiOn = (Button)findViewById(R.id.wifiOn);• wifiOn.setOnClickListener(new View.OnClickListener() {– @Override– public void onClick(View v) {• Log.e("debug","turning wifi on");• adHocConnectionManager.turnWifiOn();

– }});

• Button wifiOff = (Button)findViewById(R.id.wifiOff);• wifiOff.setOnClickListener(new View.OnClickListener() {– @Override– public void onClick(View v) {• Log.e("debug","turning wifi off");• adHocConnectionManager.turnWifiOff();

– }});

• }

IPAddressManager

• Make new class, IPAddressManager• Add member variables

– private Context context = null;– public String baseDir = null;– String ip = null;

• Constructor– public IPAddressManager(Context _context, WifiManager _wifiManager, String _baseDir) {

• context = _context;• baseDir = _baseDir;• WifiInfo wifiInfo = _wifiManager.getConnectionInfo();• Log.e("DEBUG","current mac: "+wifiInfo.getMacAddress());• ip = makeIPAddressFromMac(wifiInfo.getMacAddress());

– }• Two public functions: setStaticIP and setDynamicIP

– public void setDynmaicIP() {• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_USE_STATIC_IP, "0");

– }– public void setStaticIP() {

• // even if dns is not required and there is no default gateway, these parameters must be set. So we set them this like this• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_STATIC_IP, makeIPAddressFromMac(ip));• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_STATIC_NETMASK, "255.255.0.0");• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_STATIC_DNS1, "208.67.222.222");• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_STATIC_DNS2, "208.67.220.220");• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_STATIC_GATEWAY, "192.168.4.1");• Settings.System.putString(context.getContentResolver(), Settings.System.WIFI_USE_STATIC_IP, "1");• Log.e("debug","setting static IP to: "+Settings.System.getString(context.getContentResolver(), Settings.System.WIFI_STATIC_IP) );• Log.e("debug","use static is set to :"+Settings.System.getString(context.getContentResolver(), Settings.System.WIFI_USE_STATIC_IP) );

– }– // !! These function require write.settings permissions

• A private function for setting the ip address from the mac address– Using ipv6 would be better. I’ll add that later– The ip address is in the 192.168.255.255 subnet– Sometimes the mac address cannot be retrived. In this case, we try to read from a file that has saved the ip or, if that fails, generate a random ip

IPAddressManager cont• A private function for setting the ip address from the mac address

– Using ipv6 would be better. I’ll add that later– The ip address is in the 192.168.255.255 subnet– Sometimes the mac address cannot be retrived. In this case, we try

to read from a file that has saved the ip or, if that fails, generate a random ip

• private String makeIPAddressFromMac(String mac) {– File aFile = new File(baseDir+"/savedIpAddress.txt");– if (mac==null) {

• Log.e("debug","could not get mac address. checking is ip is saved in a file");• FileReader fr;• try {

– fr = new FileReader(aFile);– BufferedReader input = new BufferedReader(fr);– String line = null;– while ( (line = input.readLine()) != null) {

» String address;» address = line.trim();» String [] tokens = address.split(".");» if (tokens.length!=4) {• Random generator = new Random();• address = "192.168."+generator.nextInt(255)+"."+generator.nextInt(255);• return address;

» } else {• for (int i=0; i<4; i++) {• if (Integer.valueOf(tokens[i])>254 || Integer.valueOf(tokens[i])<0) {• Random generator = new Random();• address =

"192.168."+generator.nextInt(255)+"."+generator.nextInt(255);• return address;

• }• }

» }» return address;

– }• } catch (FileNotFoundException e) {

– Random generator = new Random();– String address = "192.168."+generator.nextInt(255)+"."+generator.nextInt(255);– return address;

• } catch (IOException e) {– //e.printStackTrace();

• }

– } else {• // continued next column

• // from first column• String delim = "[:]“;• String[] tokens = mac.split(delim); • int i1 = Integer.parseInt(tokens[4].trim(), 16);• int i2 = Integer.parseInt(tokens[5].trim(), 16);• String address = "192.168."+i1+"."+i2;• Log.e("debug","static ip address: "+address);• Writer output;// save this ip address to a file• try {– output = new BufferedWriter(new

FileWriter(aFile));– output.write( address );

• } catch (IOException e) {– Log.e("debug","could not save ip address to:

"+aFile.toString()); • }• return address;

– }– Random generator = new Random();– String address =

"192.168."+generator.nextInt(255)+"."+generator.nextInt(255);

– return address;

• }

WpaSupplicantConfManager• Disconnect from ad hoc and enable regular

infrastructure connection– public void makeConfNonAdHoc() {• Log.e("confManager","making conf without ad hoc network ");• if (initilized==false) {– Log.e("debug","WpaSupplicantConfManager should be initilized before

using");– initialize();

• }• currentConf.saveWithoutAdHocNetworks(currentConfFileName);• moveAndsetPermissionsOfConf(currentConfFileName);

– }• This class needs root access. Show a dialog if root

access seems to be missing. Also, we need cp (copy command) in /system/xbin. This can be installed by installing BusyBox– public void showRootFailed() {• AlertDialog.Builder alertbox = new AlertDialog.Builder(context);• alertbox.setMessage("Failed to copy current conf. Perhaps missing

root or /system/xbin/cp command is missing");• alertbox.setNeutralButton("Ok", new

DialogInterface.OnClickListener() {– public void onClick(DialogInterface arg0, int arg1) {» Toast.makeText(context, "app is disabled",

Toast.LENGTH_LONG).show();– }

• }); • alertbox.show();

–}

• Add new class WpaSupplicantConfManager• Add member variables– String currentConfFileName = new String();– String savedConfFileName = new String();– ConfDetails currentConf = null;– boolean initilized = false;– String baseDir = null;– Context context = null;• Constructor– public WpaSupplicantConfManager(String _baseDir,

Context _context) {• baseDir = _baseDir;• context = _context;• }

• Connect to ad hoc network– public void makeConfAdHoc(String

ssidOfAdHocNetwork) {– Log.e("confManager","making conf for ad hoc

network with ssid: "+ssidOfAdHocNetwork);– if (initilized==false) {• Log.e("debug","WpaSupplicantConfManager should be

initilized before using");• initialize();

– }– currentConf.saveWithAdHocNetwork(currentConfFile

Name,ssidOfAdHocNetwork);–moveAndsetPermissionsOfConf(currentConfFileName

);– }

Reads current .conf, set permissions, sets to connect to ad hoc or not

WpaSupplicantConfManager•Move conf from working dir to directory used by

wifi system and set permissions– public void moveAndsetPermissionsOfConf(String

fileName) {• // this function will not work correctly if the device does not have

root access• // However, lack of root access will be caught will be caught

somewhere else• Log.e("confManager","moving and setting permissions of:

"+fileName);• String copyCommand = "cp “;• copyCommand += currentConfFileName;• copyCommand += " /data/misc/wifi/wpa_supplicant.conf“;• final Runtime runtime = Runtime.getRuntime();• Process qq;• try {– qq = runtime.exec(new String[]{"/system/bin/su", "-c", copyCommand});– qq.waitFor();– qq = runtime.exec(new String[]{"/system/bin/su", "-c", "chmod 666

/data/misc/wifi/wpa_supplicant.conf"});– qq.waitFor();– qq = runtime.exec(new String[]{"/system/bin/su", "-c", "chown

system.wifi /data/misc/wifi/wpa_supplicant.conf"});– qq.waitFor();

• } catch (IOException e) {

– //e.printStackTrace();

• } catch (InterruptedException e) {– //e.printStackTrace();

• }•}

• Initialize the conf manager– gets current conf and saves it–Return false if failed, which likely means that the

device does not have root access– public boolean initialize() {• Log.e("debug","WpaSupplicantConfManager.ini");• initilized = true;• currentConfFileName = baseDir +

"/current_wpa_supplicant.conf";• savedConfFileName = baseDir + "/saved_wpa_supplicant.conf";• try {– copyCurrentWpaSupplicant(currentConfFileName);

• } catch (IOException e) {– Log.e("AdHocWifi Conf Manager","Failed to copy current conf.

Perhaps missing root");– showRootFailed();– return false;

• } catch (InterruptedException e) {– Log.e("AdHocWifi Conf Manager","Failed to copy current conf.

Perhaps missing root");– showRootFailed();– return false;

• }– Log.e("confManager","getting networks");– currentConf.getNetworksFromConf(currentConfFileName);– //Log.e("current conf",currentConf.toString());– if ( currentConf == null) {» } Log.e("Info","current wpa_supplicant.conf did not exist. Making

new one");» currentConf = new ConfDetails();» currentConf.header += "ctrl_interface=eth0\nupdate_config=1\

nap_scan=1\n\n";» currentConf.ap_scan = 1;

WpaSupplicantConfManager continued• Initialize continued– Log.e("confManager","getting networks from saved:

"+savedConfFileName);– ConfDetails savedConf = new ConfDetails();– savedConf.getNetworksFromConf(savedConfFileName);– if (savedConf!=null) {• //Log.e("savedConf",savedConf.toString());• Log.e("debug","updating saved config");• // make sure all networks in the saved .conf are also in the

current.conf (we will make current into our saved)• for(int i=0; i<savedConf.networks.size(); i++) {– if (savedConf.modes.get(i)==1)» continue; // skip ad hoc networks

– boolean fd = false;– for (int j=0; j<currentConf.networks.size(); j++) {» if (savedConf.networks.get(i).equals(currentConf.networks.get(j))) {• fd = true;• break;

» }– }– if (fd==false) {» currentConf.networks.add(savedConf.networks.get(i));» currentConf.ssids.add(savedConf.ssids.get(i));» currentConf.modes.add(savedConf.modes.get(i));

– }• }

– } – currentConf.saveWithoutAdHocNetworks(savedConfFileNa

me);– return true;

• }

• public void copyCurrentWpaSupplicant(String destFile) throws IOException, InterruptedException {– Log.e("confManager","copying current conf

to: "+destFile);– String copyCommand = "cp

/data/misc/wifi/wpa_supplicant.conf ";– copyCommand += destFile;– final Runtime runtime =

Runtime.getRuntime();– Process qq;– qq = runtime.exec(new

String[]{"/system/bin/su", "-c", copyCommand});

– qq.waitFor();– qq = runtime.exec(new

String[]{"/system/bin/su", "-c", "chmod 777 "+destFile});

– qq.waitFor();

• }

ConfDetails• WpaSupplicantConfManager uses a subclass named ConfDetails

that holds the information contained in the .conf file• Public functions include

– toString– saveWithoutAdHocNetworks(String fileName)– saveWithAdHocNetwork(String fileName, String

ssidOfAdHocNetwork) – getNetworksFromConf(String fileName)– String makeApScanEqual1(String header) – String makeApScanEqual2(String header)

• public class ConfDetails {– public String header;– public List<String> ssids;– public List<String> networks;– public List<Integer> modes;– int ap_scan;

– public ConfDetails() {• header = new String();• ssids = new ArrayList<String>();• networks = new ArrayList<String>();• modes = new ArrayList<Integer>();• ap_scan = 1;• Log.e("degug","made conf detials");

– }

– public String toString() {• String S = new String();• S += header;• for (int i=0; i<networks.size(); i++ ) {• S += "mode= "+modes.get(i)+"\n";• S += networks.get(i);

• }• return S;

– }

• public void saveWithoutAdHocNetworks(String fileName) {– Log.e("confManager","saving conf without ad hoc

network to: "+fileName);– String newHeader = makeApScanEqual1(header);– //use buffering– Writer output;– try {

• output = new BufferedWriter(new FileWriter(fileName));

– try { • output.write( newHeader );• for (int i=0; i<networks.size(); i++) {

– if (modes.get(i)==1)» continue;

– output.write(networks.get(i));– if (i<networks.size()-2) {

» output.write("\n");– }

• }

– } catch (IOException e) {• // TODO Auto-generated catch block• e.printStackTrace();

– }• finally {• output.close();• }

– } catch (IOException e) {• // TODO Auto-generated catch block• e.printStackTrace();

– }• }

ConfDetails contiued• public void saveWithAdHocNetwork(String fileName, String

ssidOfAdHocNetwork) {– Log.e("confManager","saving conf with ad hoc network to: "+fileName);– String newHeader = makeApScanEqual2(header);– //use buffering– Writer output;– try {

• output = new BufferedWriter(new FileWriter(fileName));

– try { • output.write( newHeader );• String adHocNetwork = new String();• adHocNetwork += "network={\n";• adHocNetwork += "ssid=";• adHocNetwork += "\""+ssidOfAdHocNetwork+"\"\n";• adHocNetwork += "scan_ssid=1\nkey_mgmt=NONE\nmode=1\n}\n\n";• output.write( adHocNetwork );• for (int i=0; i<networks.size(); i++) {

– if (modes.get(i)==1)» continue;

– output.write(networks.get(i));– if (i<networks.size()-2) {

» output.write("\n");• }

– }– } catch (IOException e) {

• // TODO Auto-generated catch block• e.printStackTrace();

– }• finally {• output.close();• }

– } catch (IOException e) {• // TODO Auto-generated catch block• e.printStackTrace();

– }

• }

• public String makeApScanEqual1(String header) {– Log.e("confManager","making ap scan equal to 1");– if (header==null) {• Log.e("error","header is null");

– }– if (header.contains("ap_scan")) {• String newHeader = new String();• int index = header.indexOf("ap_scan");• index = header.indexOf("=",index);• newHeader = header.substring(0,index);• newHeader += "=1\n";• index = header.indexOf("\n",index);• if (index+1<header.length())– newHeader += header.substring(index+1,header.length());

• //Log.e("old header",header);• //Log.e("new header",newHeader);• return newHeader;

– } else {• String newHeader = header;• newHeader += "ap_scan=1\n";• return newHeader;

– }

• }• public String makeApScanEqual2(String header) {– Log.e("confManager","making ap scan equal to 2");– if (header.contains("ap_scan")) {• String newHeader = new String();• int index = header.indexOf("ap_scan");• index = header.indexOf("=",index);• newHeader = header.substring(0,index);• newHeader += "=2\n";• index = header.indexOf("\n",index);• newHeader += header.substring(index+1,header.length());• return newHeader;

– } else {• String newHeader = header;• newHeader += "ap_scan=2\n";• return newHeader;

– }

• }

ConfDetails continued• public ConfDetails getNetworksFromConf(String fileName) {– Log.e("confManager","getting list of networks from conf named:

"+fileName);– ConfDetails confDetails = new ConfDetails();

– File aFile = new File(fileName);– try {

• FileReader fr = new FileReader(aFile);• BufferedReader input = new BufferedReader(fr);• String line = null;• boolean networkStatementEnded = false;• boolean foundSSID = false;• boolean readingHeader = true;• while ( (line = input.readLine()) != null) {

– if (line.contains("Network")==false && line.contains("network")==false) {» //Log.e("debug","header line: "+line);» if (readingHeader) {

• confDetails.header += line + "\n"; • if (line.contains("ap_scan")) {

• String[] tokens = line.split(new String("="));• if (tokens.length!=2) {

• Log.e("ERROR","malformed wpa_supplicant.conf when searching for ap_scan=...: "+fileName);

• Log.e("line:",line);• Log.e("error","num tokens: "+tokens.length);• return null;

• }• confDetails.ap_scan = Integer.valueOf(tokens[1]);

• }» }

– } else {» readingHeader = false;» String network = new String();» network += line + "\n";

» networkStatementEnded = false;» foundSSID = false;» String ssid = null;» boolean foundMode = false;» int mode = -1;

–readingHeader = false;–String network = new String();–network += line + "\n";

–networkStatementEnded = false;–foundSSID = false;–String ssid = null;–boolean foundMode = false;–int mode = -1;

–// read each line in the network specification–while ( (line = input.readLine()) != null) {• network += line + "\n";

• if (line.contains("ssid") && !line.contains("scan_ssid")) {– String[] tokens = line.split(new String("\""));• if (tokens.length<2 || tokens.length>3) {– Log.e("ERROR","malformed wpa_supplicant.conf when seaching for ssid=...: "+fileName);– Log.e("line:",line);– Log.e("error","num tokens: "+tokens.length);– return null;• }• ssid = tokens[1];• //Log.e("debug","ssid: "+ssid);• foundSSID = true;• }• if (line.contains("mode")) {– String[] tokens = line.split(new String("="));– if (tokens.length!=2) {

» Log.e("ERROR","perhaps malformed wpa_supplicant.conf when seaching for mode...: "+fileName);» Log.e("line:",line);» Log.e("error","num tokens: "+tokens.length);» //return null;

– } else {» mode = Integer.valueOf(tokens[1]);» foundMode = true;

– }• }• if (line.contains("}")) {– networkStatementEnded = true;– break;• }• }• if (networkStatementEnded && foundSSID) { // if false, then something is wrong– confDetails.networks.add(network);– confDetails.ssids.add(ssid);– if (foundMode) {

» confDetails.modes.add(mode);– } else {

» confDetails.modes.add(new Integer(0));– }• } else {– Log.e("error","malformed conf. networkStatementEnded="+networkStatementEnded+" foundssid: "+foundSSID);– break;

–}–}–}

ConfDetails continued• if (networkStatementEnded &&

foundSSID){• return confDetails;• } else {• return null;• }• } catch (FileNotFoundException e) {• // TODO Auto-generated catch block• Log.e("error","file not found: "+fileName); • return null; • } catch (IOException e) {• // TODO Auto-generated catch block• Log.e("error","io error");• return null; • }• } // ends getNetworksFromConf