FinalServer.c

//================================================= file = FinalServer.c ======
//= Notes: =
//= 1) This program conditionally compiles for Winsock and BSD sockets. =
//= Set the initial #define to WIN or BSD as appropriate. =
//=---------------------------------------------------------------------------=
//= Example execution: =
//= Waiting for recvfrom() to complete... =
//= Received from client: "Test cat catalog excat 123!" =
//= Sent to client: "Test dog dogalog exdog 123!" =
//=---------------------------------------------------------------------------=
//= Build: bcc32 FinalServer.c or cl FinalServer.c wsock32.lib for Winsock =
//= gcc FinalServer.c -lsocket -lnsl for BSD =
//=---------------------------------------------------------------------------=
//= Execute: catdogServer =
//=---------------------------------------------------------------------------=
//= Author(s): Kasey Kolyno and Ryan Binder =
//= University of South Florida =
//= Email: (kolyno, rbinder)@mail.usf.edu =
//=---------------------------------------------------------------------------=
//= History: KFK and RKB (11/14/15) - Genesis (from udpServer.c) =
//=============================================================================



#define BSD // WIN for Winsock and BSD for BSD sockets
//----- Include files --------------------------------------------------------
#include <stdio.h> // Needed for printf()
#include <ctype.h> //Needed for isalpha() and isdigit()
#include <string.h> // Needed for strcpy()
#include <stdlib.h> // Needed for exit() and rand()
#ifdef WIN
#include <windows.h> // Needed for all Winsock stuff
#endif
#ifdef BSD
#include <sys/types.h> // Needed for sockets stuff
#include <netinet/in.h> // Needed for sockets stuff
#include <sys/socket.h> // Needed for sockets stuff
#include <arpa/inet.h> // Needed for sockets stuff
#include <fcntl.h> // Needed for sockets stuff
#include <netdb.h> // Needed for sockets stuff
#endif
//----- Defines --------------------------------------------------------------
#define PORT_NUM 1050 // Arbitrary port number for the server
int checkRequest(char *b); //Checks what user is requesting
int testString (char *s); //Tests if username is alphanumeric
//===== Main program =========================================================
int main() {
  #ifdef WIN
	WORD wVersionRequested = MAKEWORD(1, 1); // Stuff for WSA functions
	WSADATA wsaData; // Stuff for WSA functions
	#endif
	int server_s; // Server socket descriptor
	struct sockaddr_in server_addr; // Server Internet address
	struct sockaddr_in client_addr; // Client Internet address
	int addr_len; // Internet address length
	char out_buf[4096]; // Output buffer for data
	char in_buf[4096]; // Input buffer for data
	int retcode; // Return code
	#ifdef WIN
	// This stuff initializes winsock
	WSAStartup(wVersionRequested, & wsaData);
  #endif
	// Create a socket
	server_s = socket(AF_INET, SOCK_DGRAM, 0);
	if (server_s < 0) {
		printf("*** ERROR - socket() failed \n");
		exit(-1);
	}
	// Fill-in my socket's address information
	server_addr.sin_family = AF_INET; // Address family to use
	server_addr.sin_port = htons(PORT_NUM); // Port number to use
	server_addr.sin_addr.s_addr = htonl(INADDR_ANY); // Listen on any IP address
	retcode = bind(server_s, (struct sockaddr * ) & server_addr,
	sizeof(server_addr));
	if (retcode < 0) {
		printf("*** ERROR - bind() failed \n");
		exit(-1);
	}
	
	FILE *file;
	
	//Loop forever
	while (1) {
		//open file
		file = fopen("usernames.txt", "a+");

		// Wait to receive a message from client
		printf("Waiting for recvfrom() to complete... \n");
		addr_len = sizeof(client_addr);
		retcode = recvfrom(server_s, in_buf, sizeof(in_buf), 0, (struct sockaddr * ) & client_addr, & addr_len);
		if (retcode < 0) {
			printf("*** ERROR - recvfrom() failed \n");
			exit(-1);
		}
		printf(" Received from client: %s \n", in_buf);
    
    	char buffer[400];
    	char *test = buffer;
		
		switch(checkRequest(in_buf))
		{
			case 1:
				if(testString(&in_buf))
				{
					fprintf(file, "%s\n", in_buf);
					sprintf(buffer, "ROK;");
					strcpy(out_buf, buffer);
				}
				else
				{
					sprintf(buffer, "INU;");
					strcpy(out_buf, buffer);
				}
				break; 
			case 2:
				
				break;
			case 3:
				
				break;
			case 4:
				
				break;
		}
		
		fclose(file);

		// Send out_buf to the client using the server socket
		retcode = sendto(server_s, out_buf, (strlen(out_buf) + 1), 0, (struct sockaddr * ) & client_addr, sizeof(client_addr));
		if (retcode < 0) {
			printf("*** ERROR - sendto() failed \n");
			exit(-1);
		}
		printf(" Sent to client: %s \n", out_buf);
	}
	// Close all open sockets
	#ifdef WIN
	retcode = closesocket(server_s);
	if (retcode < 0) {
		printf("*** ERROR - closesocket() failed \n");
		exit(-1);
	}
  #endif
  #ifdef BSD
	retcode = close(server_s);
	if (retcode < 0) {
		printf("*** ERROR - close() failed \n");
		exit(-1);
	}
  #endif
  #ifdef WIN
	// This stuff cleans-up winsock
	WSACleanup();
  #endif
	// Return zero and terminate
	return (0);
}

int checkRequest(char * b) {
	int n; // Length of string b
	int i; // Loop index
	// Get length of string b
	n = strlen(b);
	// Checks the message header from the client
	for (i = 0; i <= n; i++) {
		if ((b[i] == 'R') && (b[i + 1] == 'E') && (b[i + 2] == 'G')) 
		{
			//First 3 chars are REG, corresponds to registering a username
			return 1;
		}
		else if((b[i] == 'U') && (b[i + 1] == 'N') && (b[i + 2] == 'R'))
		{
			//First 3 chars are UNR, corresponds to un-registering a username
			return 2;
		}
		else if((b[i] == 'Q') && (b[i + 1] == 'U') && (b[i + 2] == 'O'))
		{
			//First 3 chars are QUO, corresponds to asking for stock quotes
			return 3;
		}
	}
}

//make function that takes string and checks for alphanumeric 
//If not return 0, if is return 1
int testString(char *s)
{
   int i = 0; //Counter for loop
   int j = 0; //Counter 
   int strLength = 0; //Holds length of string inputted
   int userLength = 0; //Holds length of just username

   strLength = strlen(s); //Get length of string entered   
   char tmp[strLength - 5]; //Array to hold only the username

   printf("strLength = %d \n", strLength); //debug
   for(i = 0; i < strLength; ++i) //debug
   {
      printf("s[i] = %c \n", s[i]); 
   }

   for(i = 0; i < strLength; ++i) //Gets just the username
   {
      if(i == 0 || i == 1 || i == 2 || i == 3) //Skip the first 4 chars
      {
         continue;
      }
      else if(i == strLength - 1) //Skip the last char which is a semicolon
      {
         continue;
      }
      else
      {
         tmp[j] = s[i];
         printf("tmp array now holds: %c \n", tmp[j]); //debug
         ++j;
      }
   }

   userLength = strlen(tmp); //THIS IS ALWAYS 6 FOR SOME STUPID REASON
   printf("userLength = %d \n", userLength); //debug

   for(i = 0; i < userLength; ++i)
   {
      printf("Dis is in da array: %c \n", tmp[i]);
   }

   for(i = 0; i < userLength; ++i)
   {
      if(isalpha(tmp[i]))
      {
         printf("alpha: %c \n", tmp[i]);
         continue;
      }
      else if(isdigit(tmp[i]))
      {
         printf("numeric: %c \n", tmp[i]);
         continue;
      }
      else if(tmp[i] == '\0')
      {
         printf("null terminal: \n");
         continue;
      }
      else
      {
         printf("Invalid username ya fuq! %c \n", tmp[i]);
      }
   }
}