Assignment 3 UDP and TCP sockets

Programming Assignment 3

Objective of this assignment:
• Develop and implement a simple application using UDP and TCP sockets. The application using UDP sockets was
developed for Programming Assignment 2. The application using TCP sockets is due for this Programming Assignment
3.
What you need to do:
1. Implement a simple UDP Client-Server application (Done for Programming Assignment 2)
2. Implement a simple TCP Client-Server application (this Programming Assignment 3)
Objective:
The objective is to implement a client-server application using a safe method: start from a simple working code
for the client and the server. You must slowly and carefully bend (modify) little by little the client and server
alternatively until you achieve your ultimate goal. You must bend and expand each piece alternatively the
way a black-smith forges iron. From time to time save your working client and server such that you can
roll-back to the latest working code in case of problems. Failing to follow this incremental approach may result in
a ball of wax impossible to debug in case your program does not behave or work as expected.
For this programming assignment, you are advised to start from the Friend client and server application to
implement the calculator server. You implemented the calculator server using UDP for Programming Assignment 2). Now,
you must use TCP for this Programming Assignment 3.
Part A: Datagram socket programming (Done for Programming Assignment 2) >>>> See Part B
The objective is to design a Calculating Server (CS). This calculating server performs bitwise boolean and
arithmetic computations requested by a client on 16-bit signed integers. Your server must offer the following operations:
1) addition (+), 2) subtraction (-), 3) bitwise OR (|), 4) bitwise AND (&), 5) Shift Right (>>), and 6) Shift Left (<<).
A client request will have the following format:
Field TML Request ID Op Code Number Operands Operand 1 Operand 2
Size (bytes) 1 1 1 1 2 2
Where
1) TML is the Total Message Length (in bytes) including TML. It is an integer representing the total number of bytes
in the message.
2) Request ID is the request ID. This number is generated by the client to differentiate requests. You may use a
variable randomly initialized and incremented each time a request is sent.
3) Op Code is a number specifying the desired operation following this table
Operation + - | & >> << ~
OpCode 0 1 2 3 4 5 6
4) Number Operands is the number of operands: 2 for (+, -, |, &) and shifts. It is 1 for ~ (NOT).
5) Operand 1: this number is the first or unique operand for all operations.
6) Operand 2: this number is the second operand for operations (+, -, |, &, <<, >>). It is the number of bits to shift
by for the shift operations. This operand does NOT exist for the ~ (NOT) operation.
Operands are sent in the network byte order (i.e., big endian).
Hint: create a class object Request like "Friend", but with the information needed for a request.....
Below are two examples of requests
Programming Assignment 3

Request 1: suppose the Client requests to perform the operation 240 >> 4, i.e., shift the number 240 right by 4 bits (if
this is the 7th request):
0x08 0x07 0x04 0x02 0x00 0xF0 0x00 0x04
Request 2: suppose the Client requests to perform the operation 240 – 160 (if this is the 9th request):
0x08 0x09 0x01 0x02 0x00 0xF0 0x00 0xA0
The Server will respond with a message with this format:
Total Message Length (TML) Request ID Error Code Result
one byte 1 byte 1 byte 4 bytes
Where
1) TML is the Total Message Length (in bytes) including TML. It is an integer representing the total numbers of
bytes in the message.
2) Request ID is the request ID. This number is the number that was sent as Request ID in the request sent by the
client.
3) Error Code is 0 if the request was valid, and 127 if the request was invalid (Length not matching TML).
4) Result is the result of the requested operation.
In response to Request 1 below
0x08 0x07 0x04 0x02 0x00 0xF0 0x00 0x04
the server will send back:
0x07 0x07 0x00 0x00 0x00 0x00 0x0F
In response to Request 2,
0x08 0x09 0x01 0x02 0x00 0xF0 0x00 0xA0
the server would send back:
0x07 0x09 0x00 0x00 0x00 0x00 0x50
a) Repetitive Server: Write a datagram Calculating Server (ServerUDP.java) in java. This server
must respond to requests as described above. The server must run on port (10010+GID) and could
run on any machine on the Internet. GID is your Canvas team #. The server must accept a command
line of the form: java ServerUDP portnumber where portnumber is the port where the server
should be working. For example, if your Group ID (GID) is 13 then your server must listen on Port
# 10023.
Whenever a server gets a request, it must:
i. print the request one byte at a time in hexadecimal (for debugging and grading purpose)
ii. print out the request in a manner convenient for a typical Facebook user: the request ID and
the request (operands and required operation)
b) Write a datagram client (ClientUDP.java) in java:
i. Accepts a command line of the form: java ClientUDP servername PortNumber where
servername is the server name and PortNumber is the port number of the server. Your
program must prompt the user to ask for an Opcode, an Operand1 and if needed an
Operand2 where OpCode is the opcode of the requested operation (See the opcode table).
Operand1 and Operand2 (if applicable) are the operands. For each entry from the user,
your program must perform the following operations:
Programming Assignment 3

ii. form a message as described above
iii. send the message to the server and wait for a response
iv. print the message one byte at a time in hexadecimal (for debugging and grading purpose)
v. print out the response of the server in a manner convenient for a typical Facebook user: the
request ID and the response
vi. print out the round trip time (time between the transmission of the request and the reception
of the response)
vii. prompt the user for a new request.
Part B: TCP socket programming (Due for THIS Programming Assignment 3)
Repeat part A using TCP sockets to produce (ServerTCP.java, ClientTCP.java).
How to get started?
1) Download all files (UDP sockets) to run the "Friend" application used in Module 2 to illustrate how any class
object can be exchanged: Friend.java, FriendBinConst.java, FriendDecoder.java, FriendDecoderBin.java, SendUDP.java, and
RecvUDP.java.
2) Compile these files and execute the UDP server and client. Make sure they work
3) Create a new folder called Request and duplicate inside it ALL files related to the Friend class object
4) Inside the Folder Request, change ALL occurrences of "Friend" with "Request" including the file names.
3) Adapt each file to your calculator application. Replace the fields used by Friend with the fields used by a request.
4) Aim to have the client send one request and have the server understand it (just like what we did with a friend
object).
5) When your server will receive and print out correctly a request, then you need to send back a response...
6) Create a class object Response....
Programming Assignment 3

Report
• Write a report. The report should not exceed 2 pages.
• Your report state: whether your programs work or not (this must be just ONE sentence). If your program does not work,
explain the obstacles encoutered.
What you need to turn in:
• Electronic copy of all your source programs (standalone). In addition, put all the source programs in a folder that you name
with your concatenated last name and first name. Zip the folder and submit it TOO. The grader should see on Canvas all
your source programs separately AND a zip folder containing all the source programs needed to compile and execute your
program.
• Electronic copy of the report (including your answers) (standalone). Submit the file as a Microsoft Word or PDF file.
Grading
1) UDP/TCP client is worth 40% if it works well: communicates with YOUR server. Furthermore, screenshots of
your client and server running on Tux machines must be provided. The absence of screenshots or screenshots on
machines other than the Tux machines will incur a 15% penalty.
2) UDP/TCP client is worth 10% extra if it works well with a working server from any of your classmates.
1) UDP/TCP server is worth 40% if it works well: communicates with YOUR client. Furthermore, screenshots of
your client and server running on Tux machines must be provided. The absence of screenshots or screenshots on
machines other than the Tux machines will incur a 15% penalty.
2) UDP/TCP server is worth 10% extra if it works well with a working client from any of your classmates.