CS557

Take-Home Final Examination

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Introduction

The purpose of this assignment is to extend client and server programs that communicate using windows sockets and the TCP protocol. Working basic client and server code is provided as:

final_01.zip - A server that sends each new connection off to its own thread to be handled while the main thread sits in a loop accepting connections.
final_02.zip - A client that uses blocking sockets.

These sample programs are based on implementations from here.

As these programs are currently written:

• The server waits for client connections. When it receives a client connection, it echos the message sent back to the client.
• The client sends a single message to the server. It waits for the message to be returned and verifies that the message returned is the same as the one sent. The client then shuts down in three seconds.

Both client and server programs require command line arguments of:

• IP address or name of the server.
• Port number over which the client and server will communicate.

Server Modifications Required

The server will continue to act as an echo server for the client. You will need to add:

• Code to keep track of the total number of bytes received by all executing threads. Keep track of the total bytes in a glocbal variable using P/V operations of a mutex to protect the byte count from race conditions.
• Code to keep track of the number of active clients at any time. Keep track of the active clients in a glocbal variable using P/V operations of a mutex to protect this variable from race conditions.
• Create a separate thread of execution in the server to report the total received byte count and active client count every 10 seconds. This counts should be output to standard out.
• The client should be other wise silent with respect to output.

Client Modification Required

The client currently sends a single message, waits for it's return and then shuts down. You will modify the client to spawn a variable number of threads, each of which communicate with the echo server a fixed number of times and with a random message of fixed size. The modified client program will require command line arguments of:

• IP address or name of the server.
• Port number over which the client and server will communicate.
• Number of threads to spawn (1->32000 threads).
• Number of times to communicate with the server (1->32000 times).
• Size of random message (1->32000 characters).

Use code simular to the following to generate the random messages:

char message[SizeOfRandomMessage];
for(int i = 0; i < SizeOfRandomMessage; i++) {
	int j = rand() % 128;
	while(!isprint(j)) j = rand() % 128;
	message[i] = (char) j;
}

The client should continue to verify that the message sent is the same as the one received.

The client should be largely silent. It should only report if a message has not been verified.

DUE

This final project is due to your instructor via email by 6:30, Monday December 11, 2006.