/*
ServerHeader: returns HEADER information about an HTTP server

Distribuited according to GPL license v2.
For more details: http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
There's no implicit or explicit warranty, you use it at your own risk!

Author: Fabrizio Pani - fabph@hotmail.com


compile with:
    
    gcc ServerHeader.c -o ServerHeader
    
    or in Windows
    
    mingw32-gcc ServerHeader.c -o ServerHeader.exe -mconsole -mwindows -lws2_32
    
        
    from Dev-Cpp pass the following options:
      compilatore: -mwindows -console
      linker: -lws2_32 
     
    */
    
    
    
    #include<stdio.h> //for puts(), getchar(), printf(), fprintf(), perror()
    #include<stdlib.h>//for system()
    #include<string.h> //for memset()
    #define BUFSIZE 512 //MAX BYTES at once
    #define MIN_VER 5   //Minor version
    #define MAJ_VER 0   //Major version
#ifdef _WIN32
    #include <winsock.h>
    WSADATA wsaData;
    WORD    wVersionRequested;
    DWORD dwError;
#else
    #include<sys/socket.h> //for structures, socket(), connect(), send(), recv(), 
    #include<netdb.h> //for herror(), hostent structure, gethostbyname()
    #include<netinet/in.h> //for ntohs(), htons()
    #include<errno.h> //for perror() errors
#endif    
    
   void cls(void);
   void header(void); 
    
int main(int argc,char *argv[]){
    
    
    short int sockd,retop;
    unsigned int port=80;
    struct hostent *hp;
    struct sockaddr_in address;
    char* HTTP_MSG="GET / HTTP/1.0\n\n";
    char **parg; 
    char buf[BUFSIZE];

cls();     
header();


     
#ifdef _WIN32
    wVersionRequested=MAKEWORD(2,2);             
                                         
if(WSAStartup(wVersionRequested,&wsaData)<0){
    dwError=WSAGetLastError();                                         
    printf("Unable to initialize winsock\r\n%ld",dwError);       
         
    return 1;
      
                                             }                                      
#endif     

                 
if(argc>3||argc<2){
     fprintf(stderr,"Usage: ServerHeader <IP address> or <host name>\n");
     fprintf(stderr,"Usage: ServerHeader <IP address> or <hostname> <port number> (default 80)\n");
      return 1;
                   }         
        
        
if(argc==3){
            
parg=&argv[2];
port=atoi(*parg); //conversion into integer
        
        if (port<0 || port>65535){                
              puts("\nPlease insert a port number between 0 and 65535\n"); 
              return 1;
              }
  
 
          }


if ((hp=gethostbyname(argv[1])) == NULL) {  // get IP address 


#ifdef _WIN32

     dwError = WSAGetLastError();
        
      switch(dwError){
                      
       case WSAHOST_NOT_FOUND:
           printf("Host not found\n");
       break;    
               
       case WSANO_DATA:
           printf("No data record found\n");
       break;        
            
       default:
           printf("Function failed with error: %ld\n", dwError);
                  }   
#else
     herror("IP address resolution error: ");
#endif     
     
     
     
       return 1;
    }
                       
    
    
              
sockd=socket(AF_INET,SOCK_STREAM,0);
        
        if(sockd==-1){
                      
            #ifdef _WIN32
		               dwError = WSAGetLastError();
                       fprintf(stderr,"Socket error: %ld\n",dwError);       
                       WSACleanup();
           #else
                       perror("Socket error: ");       
            #endif 
            printf("\n\nPress enter to exit");
            getchar();
            return 1;
            
                }            

address.sin_family = AF_INET;                //host byte order
address.sin_port = htons((u_short)port);    // short  network byte error 
address.sin_addr = *((struct in_addr *)hp->h_addr);
memset(address.sin_zero, '\0', sizeof(address.sin_zero));


    


printf("\nConnecting to : %s\n", inet_ntoa(*((struct in_addr *)hp->h_addr)));
printf("Port : %d\n", ntohs(address.sin_port));


retop=connect(sockd, (struct sockaddr *) &address,sizeof(address));
	     
 if(retop==-1){
	     
		          #ifdef _WIN32
		               dwError = WSAGetLastError();
                       fprintf(stderr,"\nConnection error: %ld\n",dwError);       
                       WSACleanup();
                   #else
                       perror("Connection error: ");       
                   #endif 
                   if(sockd)
                      close(sockd); 
                   puts("Press enter to exit");
                   getchar();
			       return 1;
			       
			         }    

printf("\n");
retop=send(sockd,HTTP_MSG,strlen(HTTP_MSG),0);	         

      if(retop==-1){
	               
		           #ifdef _WIN32
		               dwError = WSAGetLastError();
                       fprintf(stderr,"Server communication error: %ld\n",dwError);       
                       WSACleanup();
                       #else
                       perror("Server communication error: ");       
                   #endif 
                   if(sockd)     
                     close(sockd); 
                   printf("\n\nPress enter to exit");
                   getchar();
			       return 1;
			       
			         }    
			         
	for(;;) {

        retop = recv(sockd, buf, BUFSIZE-1, 0);
        
        if(retop){
           printf("%s",buf);
           printf("\n\nPress ENTER to continue..");
           getchar();
                     }    
               
        
        else if (retop ==-1){
             #ifdef _WIN32
		               dwError = WSAGetLastError();
                       fprintf(stderr,"Reception error: %ld\n",dwError);       
                       WSACleanup();
                       #else
                       perror("Reception error: ");       
                   #endif 
            return 1;
            
                   }
            
          
        else { 
            printf("\n\nConnection closed\n");
            break;
             }
            

    } 
		         
	
        if(sockd)
                 close(sockd);           

		#ifdef _WIN32
                    WSACleanup();
        #endif 	         
                  
        printf("\n\nPress enter to exit");
        getchar();

 return 0;
        
 }   
 
void cls(){
//portable way to clear screen (at least on Windows, and Unix systems)


#ifdef _WIN32
       system("cls");
#else
       system("clear");       
#endif     
     }



void header(){
      
char* msg="This utility returns the data header of an HTTP server.\nIt's distribuited according to GPL license v2.\nFor more details: http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt\nThere's no implicit or explicit warranty, you use it at your own risk!\n\nAuthor: Fabrizio Pani - fabph@hotmail.com\n\n";
printf("ServerHeader %d.%d\n %s",MAJ_VER, MIN_VER,msg);

      
      }