/* Connection Related Server */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>


struct Message_header {
 struct sockaddr_in mps;
 struct sockaddr_in mpr;
 int sessionID;
};

/*
struct Data{
int sessionID;
char msg_type;
char msg_size;
char data[1024];
};

*/

main(int argc, char * argv[])
{
	
	int sockfd1;
	int msgsock;
	int sockfd2;
	int length;
	int rval;
	int crs_portno;
	int mpr_portno;
	struct sockaddr_in crserver;
	struct sockaddr_in mps;
	struct sockaddr_in mpr;
	struct hostent * hp;
  	struct Message_header headr;
  
	char frombuf[1024];
	char tobuf[1024];
	char * mpr_name;

	
	sockfd1 = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd1 < 0) {
	  perror("Error opening socket\n");
	  exit(1);
	}
	
	crs_portno = 1027;
	crserver.sin_family = AF_INET;
	crserver.sin_addr.s_addr = INADDR_ANY;
	crserver.sin_port = htons(crs_portno);

	if(bind(sockfd1, (const struct sockaddr *) &crserver, 
sizeof(crserver))) {
	  perror("Error binding socket to CRS\n");
	  exit(1);
	}

	length = sizeof(crserver);

	if(getsockname(sockfd1, (const struct sockaddr *) &crserver, 
&length)) {
          perror("Error getting socket name");
          exit(1);
        }
        printf("CRS is listening to port #: %d\n",ntohs(crserver.sin_port));

	listen(sockfd1, 5);

	while(1)
	{
	msgsock = accept(sockfd1, (struct sockaddr *) &mps, &length);

	if(msgsock < 0){
	  perror("Accept error");
	  exit(1);
	}
	
	sockfd2 = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd2 < 0) {
	    perror("Error opening socket\n");
	    exit(1);
	}	
	
	if(fork() == 0) {
	
	sprintf(tobuf, "CRS is ready to accept message\n");
	write(msgsock, tobuf, sizeof(tobuf)-1);
	
	
  /*	do{
          rval = read(msgsock, &headr, sizeof(headr)); 
	} while(rval < 0);

        here code to identify the mpr 
          
   	headr.mpr = mpr;   populate the mpr structure  
	
	sprintf(tobuf, "ACK from CRS: Received header\n");
	write(msgsock, tobuf, sizeof(tobuf)-1);  */

	/* read data from mps */	
	do{
 	   rval = read(msgsock, frombuf, sizeof(frombuf)-1);
	} while(rval < 0);
	printf("%s\n", frombuf);

	/* copy the reply from MPS to tobuf */
	strcpy(tobuf, frombuf);
	
	mpr_name = "crestone.uccs.edu";
	mpr_portno = 1050;
	hp = gethostbyname(mpr_name);
	if(hp == 0) {
	 fprintf(stderr, "%s: unknown host\n", mpr_name);
	 exit(2);
	}

	memcpy(&mpr.sin_addr, hp->h_addr, hp->h_length);

	mpr.sin_family = AF_INET;
	mpr.sin_port = htons(mpr_portno);	

	length = sizeof(mpr);

	if(connect(sockfd2, (const struct sockaddr *) &mpr, length) < 0) {
	  perror("Error connecting to socket\n");
	  exit(1);
	}

	/* read Ready msg from MPR */
	do{
	  rval = read(sockfd2, frombuf, sizeof(frombuf)-1);
	} while(rval < 0);
	printf("%s\n",frombuf);
	
	if(write(sockfd2, tobuf, sizeof(tobuf)-1) < 0 ) {
            perror("Error writing to MPR");
	    exit(1);
	}
     } /* end of child process */

    } /* end while */



} /* end main */