TCP port number>
If the input department name
could be found, decide which
backend server contains related
information about the input
department name: shows up in backend server <
Backend Server ID>
Main Server has sent searching result to client
using TCP over port
Table 3. Client 1 or Client 2 on-screen messages

Event On-screen Messages
Booting up(only while starting) Client is up and running.
Enter Department Name:
After sending Department name to
Main Server:
Client has sent Department to Main
Server using TCP.
If input Department cannot be
found:
not found.
If input Department can be found: Client has received results from Main Server:
is associated with backend server
.
After the last query ends: -----Start a new query-----
Enter Department Name:
ASSUMPTIONS
1. You must start the processes in this order: Main-server, Client 1, and Client 2.

2. list.txt is created before your program starts.

3. If you need to have more code files than the ones that are mentioned here, please use
meaningful names and all small letters and mention them all in your README file.

4. You can use code snippets from Beej’s guide to network programming in your project.
However, you need to mark the copied part in your code and mention in README.

5. When you run your code, if you get the message “port already in use” or “address already
in use”, please first check to see if you have a zombie process (see following). If you do not
have such zombie processes or if you still get this message after terminating all zombie
processes, try changing the static TCP port number corresponding to this error message (all
port numbers below 1024 are reserved and must not be used). If you must change the port
number, please do mention it in your README file and provide reasons for it.
6. You may create zombie processes while testing your codes, please make sure you kill them
every time you want to run your code. To see a list of all zombie processes, try this command:
ps -aux | grep developer
Identify the zombie processes and their process number and kill them by typing at the
command-line:
kill -9
REQUIREMENTS
1. Do not hardcode the TCP port numbers that are to be obtained dynamically. Refer to
Table 1 to see which ports are statically defined and which ones are dynamically assigned. Use
getsockname() function to retrieve the locally bound port number wherever ports are assigned
dynamically as shown below:

/*Retrieve the locally-bound name of the specified socket and store it
in the sockaddr structure*/
getsock_check=getsockname(TCP_Connect_Sock,(struct sockaddr *)&my_addr,
(socklen_t *)&addrlen);
//Error checking
if (getsock_check== -1) { perror("getsockname"); exit(1);
}
2. The host name must be hard coded as localhost (127.0.0.1) in all codes.

3. Your client should keep running and ask to enter a new request after displaying the previous
result, until the TAs manually terminate it by Ctrl+C. The backend servers and the Main server
should keep running and be waiting for another request until the TAs terminate them by Ctrl+C.
If they terminate before that, you will lose some points for it.

4. All the naming conventions and the on-screen messages must conform to the previously
mentioned rules.

5. You are not allowed to pass any parameter or value or string or character as a command-
line argument.

6. All the on-screen messages must conform exactly to the project description. You should
not add anymore on-screen messages. If you need to do so for the debugging purposes, you
must comment out all the extra messages before you submit your project.

7. Using fork() to create a child process when a new TCP connection is accepted is mandatory
and everyone should support it. This is useful when different clients are trying to connect to
the same server simultaneously.

8. Please do remember to close the socket and tear down the connection once you are done
using that socket.
Programming Platform and Environment

1. All your submitted code MUST work well on the provided virtual machine Ubuntu.

2. All submissions will only be graded on the provided Ubuntu. TA won’t make any updates
or changes to the virtual machine. It’s your responsibility to make sure your code works well
on the provided Ubuntu. “It works well on my machine” is not an excuse and we don’t care.

3. Your submission MUST have a Makefile. Please follow the requirements in the following
“Submission Rules” section.
Programming Languages and Compilers
You must use only C/C++ on UNIX as well as UNIX Socket programming commands and
functions. Here are the pointers for Beej's Guide to C Programming and Network Programming
(socket programming):
(If you are new to socket programming please do study this tutorial carefully as soon as possible
and before starting the project)

You can use a Unix text editor like emacs or gedit to type your code and then use compilers such
as g++ (for C++) and gcc (for C) that are already installed on Ubuntu to compile your code. You
must use the following commands and switches to compile yourfile.c or yourfile.cpp. It will make
an executable by the name of "yourfileoutput”.
gcc -o yourfileoutput yourfile.c
g++ -o yourfileoutput yourfile.cpp
Do NOT forget the mandatory naming conventions mentioned before!