/* Multipath Sender => 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 mps_portno;
        struct sockaddr_in crs;
        struct sockaddr_in mpsender;
        struct sockaddr_in mpr;
	struct hostent * hp;
        struct Message_header headr;
 /*	struct Data datapacket;
 */ 
        char frombuf[1024];
        char tobuf[1024];
	char * crs_name;

   /*	printf("format: mps crs1_hostname crs1_protno csr2_hostname 
crs2_portno ...\n);  */

	/* hard code all the connections to CRS's  */

	sockfd2 = socket(AF_INET, SOCK_STREAM, 0);
        if(sockfd2 < 0) {
          perror("Error opening socket\n");
          exit(1);
        }
		
	/* Populate crs1,crs2,crs3... from command line arguments  */	
   
      	crs_name = "wetterhorn.uccs.edu";
	crs_portno = 1027;
	hp = gethostbyname(crs_name);
	if(hp == 0) {
	 fprintf(stderr, "%s: unknown host\n", crs_name);
	 exit(2);
	}
	
	memcpy(&crs.sin_addr, hp->h_addr, hp->h_length);
	crs.sin_family = AF_INET;
	crs.sin_port = htons(crs_portno);	

        length = sizeof(mpsender);
        if(connect(sockfd2, (struct sockaddr *) &crs, length) < 0) {
          perror("Error connecting to socket\n");
          exit(1);
        }
	
	/* Wait for the ready message from CRS */
	do{
	  rval = read(sockfd2, frombuf, sizeof(frombuf)-1);
	} while(rval < 0);
	printf("%s\n", frombuf);
	rval = 0;
	
	 /* reset values */

	/* create a socket to accept connections from various MPRs  */

        sockfd1 = socket(AF_INET, SOCK_STREAM, 0);
        if(sockfd1 < 0) {
          perror("Error opening socket\n");
          exit(1);
	}

	mps_portno = 1025;
        mpsender.sin_family = AF_INET;
        mpsender.sin_addr.s_addr = INADDR_ANY;
        mpsender.sin_port = htons(mps_portno);

        if(bind(sockfd1, (const struct sockaddr *) &mpsender, 
sizeof(mpsender))) {
          perror("Error binding socket to MPS\n");
          exit(1);
        }
        
        length = sizeof(mpsender);
        
	if(getsockname(sockfd1, (const struct sockaddr *) &mpsender, 
&length)) {
          perror("Error getting socket name");
          exit(1);
        }
        printf("MPSender(server) is listening to port #: %d\n",ntohs(mpsender.sin_port));

        listen(sockfd1,5);
          
        while(1)
        {
        msgsock = accept(sockfd1, (struct sockaddr *) &mpr, &length);

        if(msgsock < 0){
          perror("Accept error\n");
          exit(1);
        }

	if(fork() == 0) {

		do {  /* read request from MPR  */
        	rval = read(msgsock, frombuf, sizeof(frombuf)-1);
          
	        } while(rval < 0);

	printf("The request from MPR is: %s\n", frombuf);  	
	rval = 0;

	
		/* here comes the code to construct the reply
		   and chop the reply into various packets  */

		sprintf(tobuf, "Hello,I am the Server\n");  /* Construct 
the reply */


		/* constructing message header  

     		headr.mpr = mpr;
		headr.mps = mpsender;
         	headr.sessionID = ?;   
	
	
		write(sockfd2, &headr, sizeof(headr));   send the 
         Message_header stucture to CRS
         replicate this piece of code for so many number of CRSs  */
	
	        
		/* write to crs */
		if(write(sockfd2, tobuf, sizeof(tobuf)-1) < 0) {
             
	          perror("Error writing to crs"); 
		  exit(1);
		}
	/* read acknowledgement from MPR */
	do{
	    rval = read(msgsock, frombuf, sizeof(frombuf)-1);
	} while(rval < 0);
	printf("%s", frombuf);	
	rval = 0;
	
	
	
           if(write(msgsock, tobuf, sizeof(tobuf)-1) < 0) {
		perror("Error writing to mpr");
		exit(1);
	       }	

 	/*	while(/* no more packets) {

		write(sockfd2, &datapacket, strlen(datapacket));  /* send the data packets to CRS
		}

	        while(/* no more packets) {
        
        	write(msgsock, &datapacket, strlen(datapacket));  /* send the data packets to MPR on original connection 
	        }
 	*/

	} /* end of child process */


    } /* end while */



} /* end of main */