Eclipse Error : contains native libraries that will not run on the device

Few days back I wanted to try Crittercism's NDK library and ended up facing the following error in Eclipse after following exactly the same steps given on their site.

The library 'crittercism_v4_5_1_ndk.jar' contains native libraries that will not run on the device.

The following libraries were found:

- assets/armeabi-v7a/libcrittercism-ndk.so

- assets/armeabi/libcrittercism-ndk.so

This error could be avoided by the following Steps.

Eclipse Preference ->Android->Build->Un Check "Force error when external jars contain native libraries"

Disable CellBroadcast in Cyanogenmod

The problem started last week when I started receiving Cell Broadcast alerts non stop all day. My phone is Samsung Galaxy S2 and was running on latest version of Cynogenmod. After searching in some Android forums I found a way to disable all kinds of cell broadcast by using  option in Message application.

Message->Menu->Cell Broadcast

Even after doing so the problem did not go away. Finally after lot of searching I found a way to do this. Use Terminal Emulator and execute the following commands.

su
mount -orw,remount /system
rm /system/app/CellBroadcastingReceiver.apk
reboot

UI≠UX

Difference between UI and UX




The most common misconception we come across in the workplace, in client meetings or even in the Job listings is that the terms UI and UX are interchanged and used in the wrong context. Though both the terms look and spell alike there is a substantial difference in the overall objective and scope.

User Interface (UI) is a medium of communication between a person and a system. UI encompasses approaches and elements that allows the user to interact with the system. In other terms UI can be considered as the most powerful tool that designer use to bring out a great user experience.

On the other hand User Experience (UX) is:

• The overall experience


• A combination of various interface, UI being an important one among it.


• Thrives to address everything perceived by a person

A UI designer can only solve a part of the equation by creating tools such as images, icons, text but the user experience is much larger than that and is influenced by a multitude of things such as functional performance, color scheme, ease of use etc. Hence for an organization it is very important to understand the basic difference between the two roles and hiring the right candidate with proper skill set.


Last but not the least...

This is what happens when you let a developer play the role of UI/UX designer

Initializing NIST JAIN SIP Stack

This tutorial uses NIST SIP JAIN Reference Implementation. Download the NIST source code from here.

public void init() {
try {
// Get the local IP address.
this.ip = InetAddress.getLocalHost().getHostAddress();
// Create the SIP factory and set the path name.
this.sipFactory = SipFactory.getInstance();
this.sipFactory.setPathName("gov.nist");
// Create and set the SIP stack properties.
this.properties = new Properties();
this.properties.setProperty("javax.sip.STACK_NAME", "stack");
this.properties.setProperty("gov.nist.javax.sip.TRACE_LEVEL", "32");

if(proxy != null) {
this.properties.setProperty("javax.sip.OUTBOUND_PROXY", proxy + ':' + port + '/' + protocol);
}

this.properties.setProperty(
"gov.nist.javax.sip.LOG_MESSAGE_CONTENT", "true");
this.properties.setProperty("gov.nist.javax.sip.DEBUG_LOG",
"mss-jsip-debuglog.txt");
this.properties.setProperty("gov.nist.javax.sip.SERVER_LOG",
"mss-jsip-messages.xml");
// Create the SIP stack.
this.sipStack = this.sipFactory.createSipStack(this.properties);
// Create the SIP message factory.
this.messageFactory = this.sipFactory.createMessageFactory();
// Create the SIP header factory.
this.headerFactory = this.sipFactory.createHeaderFactory();
// Create the SIP address factory.
this.addressFactory = this.sipFactory.createAddressFactory();
// Create the SIP listening point and bind it to the local IP
// address, port and protocol.
this.listeningPoint = this.sipStack.createListeningPoint(this.ip,
this.port, this.protocol);
// Create the SIP provider.
this.sipProvider = this.sipStack
.createSipProvider(this.listeningPoint);
// Add our application as a SIP listener.
this.sipProvider.addSipListener(this);
// Create the contact address used for all SIP messages.
this.contactAddress = this.addressFactory.createAddress("sip:" + this.username + "@"
+ this.ip + ";transport=tcp");
// Create the contact header used for all SIP messages.
this.contactHeader = this.headerFactory
.createContactHeader(contactAddress);
// Display the local IP address and port in the text area.
} catch (Exception e) {
e.printStackTrace();
// If an error occurs, display an error message box and exit.
System.exit(-1);
}
}

Digest authorization in SIP with MD5 Challenge

During a SIP request if the server responds with 401 Proxy Authentication Required or 401 Unauthorized then it means the client has to replay the same request again with MD5 challenge.

The client should use nonce value from the response header WWW-Authenticate.

[code]

WWW-Authenticate: Digest realm="sip.linphone.org", nonce="JbAO1QAAAAA3aDI0AADMobiT7toAAAAA", opaque="+GNywA==", algorithm=MD5, qop="auth"

[/code]

The client should use nonce to generate the MD5 challenge and make the original request again with the Authorization header.

Steps to create the MD5 Challenge

1. Create first MD5 hash using username + ":" + realm + ":" + password

[java]

String a1 = username + ":" + realm + ":" + password;
String ha1 = toHexString(mdigest.digest(a1.getBytes()));
[/java]

2. Create second MD5 hash using request_method + ":" + request_uri

[java]

String a2 = request_method.toUpperCase() + ":" + request_uri;
String ha2 = toHexString(mdigest.digest(a2.getBytes()));
[/java]

3. If qop in the response header is "auth" then the final MD5 hash is calculated using step 3a else if it is undefined or empty refer step 3b.

3a. Create the final MD5 string using ha1 + ":" + nonce + ":" + nonceCount + ":" + cNonce + ":" + qop + ":" + ha2

[java]

String finalStr = ha1 + ":" + nonce + ":" + nonceCount + ":" + cNonce + ":" + qop + ":" + ha2;
String response = toHexString(mdigest.digest(finalStr.getBytes()));
[/java]

3b. Create the final MD5 string using ha1 + ":" + nonce + ":" + ha2

[java]
String finalStr = ha1 + ":" + nonce + ":" + ha2;
String response = toHexString(mdigest.digest(finalStr.getBytes()));
[/java]

Download the complete source code from here

SIP Register Request using JAIN SIP

This tutorial uses NIST SIP JAIN Reference Implementation. Download the NIST source code from here.

Note: To understand the Authorization process for handling 401 response code from server please go through this tutorial.

REGISTER request is used to update the current location of a user on the REGISTRAR server. The application sends a REGISTER message informing the server its current location which in turn is stored in location server. When a caller calls a user the proxy server uses this information to find the location of the callee.

Register request should be sent by the client periodically. The validity of the REGISTER request is determined by the Expires header.

Flow



Sample Request

[code]
REGISTER sip:sip.linphone.org SIP/2.0
Call-ID: 0a0f14355fa76ae6435b98bfe085baf9@223.1.1.128
CSeq: 1 REGISTER
From: <sip:vkslabs@sip.linphone.org>;tag=-1427592833
To: <sip:vkslabs@sip.linphone.org>
Max-Forwards: 70
Via: SIP/2.0/TCP 223.1.1.128:5060;branch=z9hG4bK-323532-2a454f4ec2a4213f6d6928eba479521d
Contact: <sip:vkslabs@223.1.1.128;transport=tcp>
Content-Length: 0
[/code]

Now lets see how to construct the above request using the NIST SIP Stack.

First step is to create a class that implements the SIPListener. Make sure your SIP Stack is Initializing NIST JAIN SIP Stack.

1. Create Call-ID header

[java] CallIdHeader callIdHeader = this.sipProvider.getNewCallId(); [/java]

2. Create CSeq header

[java] CSeqHeader cSeqHeader = this.headerFactory.createCSeqHeader(cseq, "REGISTER"); [/java]

3. Create From header

[java] Address fromAddress = addressFactory.createAddress("sip:" + username + '@' + server);
FromHeader fromHeader = this.headerFactory.createFromHeader(fromAddress, String.valueOf(this.tag));
[/java]

4. Create To Header

[java] ToHeader toHeader = this.headerFactory.createToHeader(fromAddress, null); [/java]

5. Create Max-Forwards header

[java] MaxForwardsHeader maxForwardsHeader = this.headerFactory.createMaxForwardsHeader(70); [/java]

6. Create a Via header

[java]
ArrayList viaHeaders = new ArrayList();
ViaHeader viaHeader = this.headerFactory.createViaHeader(this.ip, this.port, "tcp", null);
viaHeaders.add(viaHeader);
[/java]

7. Create contact header

[java]
this.contactAddress = this.addressFactory.createAddress("sip:" + this.username + '@' + this.ip + "transport=tcp");
// Create the contact header used for all SIP messages.
this.contactHeader = this.headerFactory.createContactHeader(contactAddress);
[/java]

Once all the headers are created it is time to create the request itself.

[java]
request = this.messageFactory.createRequest("REGISTER sip:" + server + "SIP/2.0\r\n\r\n");
request.addHeader(callIdHeader);
request.addHeader(cSeqHeader);
request.addHeader(fromHeader);
request.addHeader(toHeader);
request.addHeader(maxForwardsHeader);
request.addHeader(viaHeader);
request.addHeader(contactHeader);
[/java]

Now that the request object is created with all the necessary headers it is time to send the request.

[java] inviteTid = sipProvider.getNewClientTransaction(request);
// send the request out.
inviteTid.sendRequest();
[/java]

Once the request is sent successfully the response will be passed to the application using the processResponse callback in SIPListener.

[java]
public void processResponse(ResponseEvent responseEvent) {
int statusCode = responseEvent.getResponse().getStatusCode();
}
[/java]

Code

[java]
public void register(Response response) {
try {
cseq++;
ArrayList viaHeaders = new ArrayList();
ViaHeader viaHeader = this.headerFactory.createViaHeader(this.ip,
this.port, "tcp", null);
viaHeaders.add(viaHeader);
// The "Max-Forwards" header.
MaxForwardsHeader maxForwardsHeader = this.headerFactory
.createMaxForwardsHeader(70);
// The "Call-Id" header.
CallIdHeader callIdHeader = this.sipProvider.getNewCallId();
// The "CSeq" header.
CSeqHeader cSeqHeader = this.headerFactory.createCSeqHeader(cseq,
"REGISTER");

Address fromAddress = addressFactory.createAddress("sip:"
+ username + '@' + server);

FromHeader fromHeader = this.headerFactory.createFromHeader(
fromAddress, String.valueOf(this.tag));
// The "To" header.
ToHeader toHeader = this.headerFactory.createToHeader(fromAddress,
null);

// this.contactHeader = this.headerFactory
// .createContactHeader(contactAddress);

request = this.messageFactory.createRequest("REGISTER sip:"
+ server + " SIP/2.0\r\n\r\n");
request.addHeader(callIdHeader);
request.addHeader(cSeqHeader);
request.addHeader(fromHeader);
request.addHeader(toHeader);
request.addHeader(maxForwardsHeader);
request.addHeader(viaHeader);
request.addHeader(contactHeader);
if (response != null) {
retry = true;
AuthorizationHeader authHeader = Utils.makeAuthHeader(headerFactory, response,
request, username, password);
request.addHeader(authHeader);
}
inviteTid = sipProvider.getNewClientTransaction(request);
// send the request out.
inviteTid.sendRequest();
this.dialog = inviteTid.getDialog();
// Send the request statelessly through the SIP provider.
//            this.sipProvider.sendRequest(request);

// Display the message in the text area.
logger.debug("Request sent:\n" + request.toString() + "\n\n");
} catch (Exception e) {
// If an error occurred, display the error.
e.printStackTrace();
logger.debug("Request sent failed: " + e.getMessage() + "\n");
}
}
[/java]

Download the complete working code from here.

Introduction to SIP

SIP stands for Session Initiation Protocol a signaling protocol defined by IETF used for controlling communication sessions. SIP is used to create, manage and terminate sessions in an IP based network. SIP is widely used in VOIP (Voice over IP) .

 

The two main entities in a SIP session are

User Agent Client

User Agent Server

There are several types of server

 

Proxy Server

Redirect Server

Registrar

Location Server

 

SIP is similar to HTTP protocol. To understand the differences lets first learn how HTTP Protocol works.

Here is a sample HTTP request

GET /index.html HTTP/1.1

Host: www.w3.org

User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:20.0) Gecko/20100101 Firefox/20.0

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8

Accept-Language: en-US,en;q=0.5

The first line is the request line which has the request method (GET), the URI that is being requested (index.html) and the protocol version (HTTP/1.1)

Following the request line is one or more request headers like Host, User-Agent etc.

An empty line break follows the request headers which is followed an options message body.

Once you understand the protocol you can mimic a browser and send a request to web server using telnet or a simple java program that uses plain socket.

TBD

Now lets take a look at SIP protocol and find out the differences between HTTP and SIP

Here is a sample SIP request

REGISTER sip:ss2.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7
Max-Forwards: 70
From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl
To: Bob <sips:bob@biloxi.example.com>
Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com
CSeq: 1 REGISTER
Contact: <sips:bob@client.biloxi.example.com>
Content-Length: 0

The first line is the request line which has the request method (REGISTER), the URI that is being requested (index.html) and the protocol version (HTTP/1.1)

Following the request line is one or more request headers like Host, User-Agent etc.

An empty line break follows the request headers which is followed an options message body.