/*
 *
 * latency
 *  show http latency
 *
 * $> ./latency www.cisco.com
 * 1069255499      12      229     244
 *
 * output: timestamp \t dns [ms] \t get [ms] \t recv [ms] \n
 *
 * parameters : 
 *  -p PORT specify http port (80 is default)
 *  -u URL specify for http get
 *  -t human timestamp
 *  -d debug
 *
 * compile    : gcc latency.c -olatency
 * author     : agramajo at sinectis dot com
 * licence    : mit 
 * history    :
 *  19/09/2003 first release
 *  19/11/2003 better output
 *  28/11/2003 add port parameter
 *  04/12/2003 add url parameter
 *
 * Copyright (c) 2003 Alejandro Gramajo
 * Under http://www.opensource.org/licenses/mit-license.html
 *
 * todo       :
 *  validate all parameters
 *  timeouts for connect/send/recv, I can't wait forever 8-)
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>
#include <string.h>
#include <getopt.h>

#define DEFPORT    80
#define BUFRECV  4000
#define BUFTIME    20
#define BUFSIZE   256
#define REQUEST  "GET %s HTTP/1.0\r\n\r\n"

long int calc_ms (struct timeval*, struct timeval*);
void print_tv (struct timeval*);
void usage (char*);

int main(int argc, char **argv) {
	int			sockfd, count;
	char			request[BUFSIZE], url[BUFSIZE];
	char			reply[BUFRECV], datetime[BUFTIME];
	struct hostent		*he;
	struct sockaddr_in	target;
	struct timeval		*tvs;     /* start  time */
	struct timeval		*tvf;     /* finish time */
	struct timezone		*tz;
	int			debug, humantime, port, c;
	long int		tdns, tsend, trecv;	
	time_t			ltime;
	struct tm		*loctime;
	extern char 		*optarg;
	extern int 		optind, opterr, optopt;

	while ((c = getopt (argc, argv, "u:tp:dh")) != -1) {
		switch (c) {
			case 'u':
				// todo: verify url (without http://)
				strncpy(url,optarg,strlen(optarg));
				break;
			case 't':
				humantime = 1;
				break;
			case 'p':
				// todo: verify that is a valid port number
				port = atoi(optarg);
				break;
			case 'd':
				debug = 1;
				break;
			case 'h':
				usage(argv[0]);
				return 1;
      			case '?':
				if (isprint (optopt)) 
					fprintf (stderr, 
						"Unknown option `-%c'.\n", 
						optopt);
				else 
					fprintf (stderr, 
						"Unknown character `\\x%x'.\n", 
						optopt); 
				return 1;
      			default:
        			usage(argv[0]);
				return 1;
      		}
	}

	if (!argv[optind]) {
		usage(argv[0]);
		exit(1);
	}

	tvs = (struct timeval  *) malloc(sizeof(struct timeval));
	tvf = (struct timeval  *) malloc(sizeof(struct timeval));
	tz  = (struct timezone *) malloc(sizeof(struct timezone));
    
	gettimeofday(tvs, tz); if (debug) print_tv(tvs);

	if ((he=gethostbyname(argv[optind])) == NULL) {
		herror("gethostbyname");
		exit(1);
	}

	gettimeofday(tvf, tz); if (debug) print_tv(tvf);
	tdns = calc_ms(tvs,tvf);

	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
		perror("socket");
		exit(1);
	}        

	target.sin_family   = AF_INET;
	target.sin_port     = port ? htons(port) : htons(DEFPORT);
	target.sin_addr     = *((struct in_addr *)he->h_addr);
	bzero(&(target.sin_zero), 8);

	gettimeofday(tvs, tz); if (debug) print_tv(tvs);

	if (connect(sockfd, (struct sockaddr *)&target,
		sizeof(struct sockaddr)) == -1) {
		perror("connect");
		exit(1);
    	}
	if (url) {
		sprintf(url, "http://%s", url);
		sprintf(request, REQUEST, url);
	} else
		sprintf(request, REQUEST, "/");

	if (debug)
		printf("debug: request=%s\n", url ? url : "/");
	
	send(sockfd, request, strlen(request), 0);

	gettimeofday(tvf, tz); if (debug) print_tv(tvf);
	tsend = calc_ms(tvs,tvf);

	gettimeofday(tvs, tz); if (debug) print_tv(tvs);

	if ((count = recv(sockfd, reply, BUFRECV, 0)) == -1) {
		perror("recv");
		exit(1);
	}

	gettimeofday(tvf, tz); if (debug) print_tv(tvf);
	trecv = calc_ms(tvs,tvf);

	if (debug>1) printf("%s", reply);

	close(sockfd);

	ltime = time(NULL);
	if (humantime) {
		loctime = localtime(&ltime);
		strftime (datetime, BUFTIME, "%Y-%m-%d %H:%M:%S", loctime);
		printf("%s\t", datetime);
	} else {
		printf("%ld\t", ltime);
    	}

	printf("%ld\t%ld\t%ld\n",tdns, tsend, trecv); 
    
	return 0;
}

long int calc_ms (struct timeval *tvs, struct timeval *tvf) {
	return  (tvf->tv_sec - tvs->tv_sec) * 1000 + 
		(tvf->tv_usec - tvs->tv_usec) / 1000;
}

void print_tv (struct timeval *tv) {
	printf("debug: %ld %ld\n", tv->tv_sec, tv->tv_usec);
}

void usage (char *program) {
	printf(
		"Usage: %s [options...] host\n"
		"Options:\n"
		" -t       human timestamp (aka YYYY-MM-DD HH:MM:SS)\n"
		" -p PORT  specify http port (80 is default)\n"
		" -u URL   specify url for http get\n"
		" -h       show this help\n"
		" -d       debug\n"
		"Output:\n"
		" timestamp \\t dns [ms] \\t get [ms] \\t recv [ms] \\n\n\n",
		program);
}