/* sender for internet stream demo */

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

#define ENDPACKET "end"

help_msg()
{
	printf("format: inetsts -[dn] hostname portno\n");
	printf("          option: n set the number packet to be sent\n");
	printf("                  d set debug mode\n");
}

main(argc, argv)
int argc;
char *argv[];
{
	int sock; 
	struct sockaddr_in server;
	struct hostent *hp, *gethostbyname();

	int n = 1;
	int i;
	char buf[1024];
	extern char *optarg;
	extern int   optind;
	int option_exist = 0;
	int c;
	int debug = 0;
	char *rcv_name;  /* receiver's socket name */
	int port_no;
	fd_set fdvar;

	/* process command line args */
	while ((c=getopt(argc,argv,"dn:")) != EOF)
	{
		option_exist = 1;
		switch(c)
		{
		case 'd':
			debug = 1;
			if (debug)
				printf("turn on debug mode.\n");
			break;

		case 'n':
			if ((n = atoi(optarg)) < 1) n = 1;
			if (debug)
				printf("The number packet to be sent is %d\n", n);
			break;
		case '?':
			help_msg();
			exit (1);
		default:
			fprintf (stderr, "unrecognized arg >%s<\n", optarg);
			help_msg();
			exit (1);
		}
	}

	printf("argc=%d\n", argc);
	if (argc < 3) {
		fprintf (stderr, "%s: require hostname and portno.\n", argv[0]);
		help_msg();
		exit (1);
	}
	rcv_name = argv[optind++];
	if ((port_no = atoi(argv[optind])) < 1025) port_no = 1025;

	if (debug) 
		printf("The receiver's host name is %s, port_no=%d\n", 
		rcv_name, port_no);

	/* create socket on which to sent */
	sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		perror("opening stream socket");
		exit(1);
	}
	/* construct name of the socket to send to 
	 * gethostbyname() returns a structure including the network address
	 * of the specified host from /etc/hosts. The port number is taken from
	 * the cmd line
	 * create name structure for the internet socket 
	 * use the name from cmd argument 
	 */
	hp = gethostbyname(rcv_name);
	if (hp == 0) {
		fprintf(stderr, "%s: unknown host",rcv_name);
		exit(2);
	}
	bcopy(hp->h_addr, &server.sin_addr, hp->h_length);
	server.sin_family = AF_INET;
	server.sin_port = htons(port_no);

	if (connect(sock, &server, sizeof(server)) < 0) {
		perror("connecting stream socket");
		exit(1);
	}
	/*send message */
	for (i=0; i< n; i++) {
		sprintf(buf, "packet %d,",i);
		FD_SET(sock, &fdvar);
		if (select(sock+1, 0, &fdvar, 0, 0) < 0) perror("select error");
		else printf("ok for writing %s\n", buf);
		if (write(sock, buf, strlen(buf)) < 0) 
			perror("writing on stream socket");
	}
	if (read(sock, buf, sizeof(buf)) < 0)
		perror("writing on stream socket");
	close(sock);
}