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

#define ECHO_PORT 7775

#define DEBUG 1

//static struct rtsocket *echo_sock;
static int echo_sock;

#define BUFSZ 1500

char buffer[BUFSZ];


/* main */
main(int argc, char *argv[]) {
        struct sockaddr_in addr;
	int ret,i;
	struct msghdr msg;
	struct iovec iov;

	echo_sock = socket(AF_INET,SOCK_DGRAM,0);

	memset(&addr,0,sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(ECHO_PORT);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);

	bind(echo_sock,(struct sockaddr *)&addr,sizeof(addr));

	fprintf(stderr,"echo_server started\n");

/*********************************************************************************/

/*        for(i = 0; i<100; i++) {
           buffer[i] = i;
        }
*/

        ret = 0;
while ( ret != 1 ) {

	memset(&msg,0,sizeof(msg));
	iov.iov_base=buffer;
	iov.iov_len=BUFSZ;
	msg.msg_name=NULL;
	msg.msg_iov=&iov;
	msg.msg_iovlen=1;
	msg.msg_control=NULL;
	msg.msg_controllen=0;
	msg.msg_name=&addr;
	msg.msg_namelen=sizeof(addr);

	ret=recvmsg(echo_sock,&msg,0);

	fprintf(stderr,"recvmsg()=%d\n",ret);
        fprintf(stderr,"%p: %i %i %i\n",iov.iov_base,((char*)iov.iov_base)[0],((char*)iov.iov_base)[1],buffer[2]);
        iov.iov_base = buffer;
        iov.iov_len = ret;


	if(ret>0){
		fprintf(stderr,"echo rcv from %08x.%d\n",(int)ntohl(addr.sin_addr.s_addr),(int)ntohs(addr.sin_port));
                fprintf(stderr,"iov_base bef.send:%p\n",iov.iov_base);

                /* forcing it to send the echo back to the echo port and not to the sending port */
                addr.sin_port = htons(ECHO_PORT);

		//s		ret=sendmsg(echo_sock,&msg,0);

                
		//s		fprintf(stderr,"sendmsg()=%d\n",ret);
                fprintf(stderr,"%p: %i %i %i\n",iov.iov_base,buffer[0], buffer[1], buffer[2]);

	}

}
/*********************************************************************************/

        close(echo_sock);
        fprintf(stderr,"echo_server stopped\n");
	return 0;              
}