/* Socket Server: Compilation: gcc server.c -o server
                   to run: server [local_port] [remote_host] [remote_port]

**** PS: The clients must be running before executing the server *****

*/


#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <netdb.h>

#define SIZE 1000 // vector size

//############################################################################################

int main(int argc, char* argv[])
{
    int
    	 S0, S1,
         loc_port,  // local port
         rem_port, // remote port
         dsr,     // descriptor of remote socket
         vector[SIZE],
         *v;

    char *host;

    struct sockaddr_in       rem_addr; // internet address
    struct sockaddr_in       loc_addr; // internet address
    struct hostent           *phost; // pointer to host entry structure


	if(argc < 3){
	  printf("Erro uso correto:\n");
	  printf("     %s <localport_number> <hostname> <port_number>\n\n", argv[0]);
	  exit(1);
	}


    //clean structure
    memset ((char *)&rem_addr,0,sizeof(rem_addr));


    //Remote Socket 	
    host = argv[2];    //Remote machine host 
    phost = gethostbyname(host);

    //fill out the socket's address information
    rem_port = atoi(argv[3]);
    rem_addr.sin_family = AF_INET; // address family
    rem_addr.sin_port = htons(rem_port);
    dsr = socket (AF_INET, SOCK_STREAM, 0);

    //vector to receive
    v = ( int * ) malloc (sizeof ( int ) * SIZE);

    //copy ip address into ip address structure
    memcpy(&rem_addr.sin_addr, phost->h_addr, phost->h_length);
	
    if (dsr < 0)
    { perror("Creating remote stream socket\n"); exit(1); }
	
    printf("Conecting on client '%s, port: %d'\n", host, rem_port);

    // make the connection
    if (connect(dsr, (struct sockaddr*) &rem_addr, sizeof(rem_addr)) < 0)
    { perror("Conecting stream socket\n"); exit(1); }	

    // Local Socket
    //fill out the socket's address information
    loc_port = atoi(argv[1]);
    loc_addr.sin_family = AF_INET;
    loc_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    loc_addr.sin_port = htons(loc_port);

    // create the socket	
    S0 = socket(AF_INET, SOCK_STREAM, 0);
    if (S0 < 0)
    { perror("Creating local stream socket"); exit(1); }

    //bind the socket into its address 	
    if (bind(S0, (struct sockaddr*) &loc_addr, sizeof(loc_addr)) < 0)
    { perror("Binding stream socket"); exit(1); }
    
    //listen for connections
    listen(S0, 1);
          		
    printf("Waiting for conection....\n");
    // accept a connection
    S1 = accept(S0, (struct sockaddr*) 0, (int*) 0);
    printf("Conection established !!!\n");

//--------------------------------------------------------------------------------------------
// send and receive messages form clients
    send(dsr, vector, SIZE, 0);	
    recv(S1, v, SIZE, 0);
    printf("Message backing to the server...\n");	
//--------------------------------------------------------------------------------------------

//close the connection
    close(dsr);
    close(S0);
    close(S1);

}

//############################################################################################