/*
  Dinko Korunic, kreator@fly.srk.fer.hr
  Wed Nov 22 18:19:16 CET 2000
  This program is under GPL licence.

  Host port connection timer developed for magazine Mreza
 */

#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <time.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/stat.h>

/* Solaris compatibility tweak */
#ifndef INADDR_NONE
# define INADDR_NONE ((unsigned long)-1)
#endif

#define MAXLINE 1 /* How much bytes to read from host */
#define MAXHOSTNAME 256 /* How long can hostname be */
/* #define MOREPRECISE /* Do measuring in msecs or just secs */

/* Connect to host. Return -1 on error, socket fd on success */
int connecthost(char *hostname, unsigned int port)
{
  struct sockaddr_in servaddr;
  struct hostent *hostptr;
  struct in_addr ip;
  int socketfd, flags, option=1;

  memset(&servaddr, 0, sizeof(servaddr));

  if (hostname==NULL)
    return -1;

  ip.s_addr=inet_addr(hostname);
  
  if (ip.s_addr!=INADDR_NONE)
    hostptr=NULL;
  else
    if ((hostptr=gethostbyname(hostname))!=NULL)
      memcpy(&ip.s_addr, hostptr->h_addr_list[0], hostptr->h_length);

  if (hostptr)
    {
      servaddr.sin_family=hostptr->h_addrtype;
      servaddr.sin_addr.s_addr=ip.s_addr;
    }
  else
    {
      if (ip.s_addr==INADDR_NONE)
	return -1;
      servaddr.sin_family=AF_INET;
      servaddr.sin_addr.s_addr=ip.s_addr;
    }

  if ((socketfd=socket(servaddr.sin_family, SOCK_STREAM, 0))==-1)
    {
      perror("Cannot open socket stream");
      exit(EXIT_FAILURE);
    }

  if ((flags=fcntl(socketfd, F_GETFL, 0))==-1)
    {
      perror("Cannot make read socket flags");
      exit(EXIT_FAILURE);
    }

  if (fcntl(socketfd, F_SETFL, flags|O_NONBLOCK)==-1)
    {
      perror("Cannot make socket nonblocking");
      exit(EXIT_FAILURE);
    }

  if (setsockopt(socketfd, SOL_SOCKET, SO_REUSEADDR, (char *)&option,
		 sizeof(option))==-1)
    perror("Cannot set socket reusable");

  servaddr.sin_port=htons(port);

  if (connect(socketfd, (struct sockaddr *)&servaddr,
	      sizeof(servaddr))==-1)
    if (errno!=EINPROGRESS)
      {
	perror("Error connecting to host");
	close(socketfd);
	return -1;
      }
  return socketfd;
}

/* Read data from host and time it. Returns -1 on error or seconds elapsed
   on success */
int readhost(char *hostname, unsigned int port, struct timeval *etime)
{
  int socketfd;
  char inbuf[MAXLINE];
  struct timeval time1, time2;

  gettimeofday(&time1, NULL);
  if ((socketfd=connecthost(hostname, port))>=0)
    {
      memset(inbuf, 0, sizeof(inbuf));
      if (read(socketfd, inbuf, MAXLINE-1)==-1)
	return -1;
      gettimeofday(&time2, NULL);
    }
  else
    return -1;
  
  close(socketfd);

  time2.tv_sec-=time1.tv_sec;
  time2.tv_usec-=time1.tv_usec;

  *etime=time2;
  
  return 0;
}

/* Loop reading from input files */
int main(int argc, char **argv)
{
  char usage[]="There should be 2 arguments:\n"
    "name of input file and name of output file.\n"
    "Input file should be like: servername port\n",
    myhostname[MAXHOSTNAME];
  time_t mytime=time(NULL);
  int myport;
  struct timeval etime;
  FILE *myinput, *myoutput;

  if (argc!=3)
    {
      fputs(usage, stderr);
      exit(EXIT_FAILURE);
    }

  if ((myinput=fopen(argv[1], "r"))==NULL)
    {
      perror("Cannot open input file");
      exit(EXIT_FAILURE);
    }

  umask(077);

  if ((myoutput=fopen(argv[2], "a"))==NULL)
    {
      perror("Cannot open output file");
      exit(EXIT_FAILURE);
    }

  fprintf(myoutput, "Statistics on %s", ctime(&mytime));

  while (fscanf(myinput, "%s %d", myhostname, &myport)!=EOF)
    {
      if (readhost(myhostname, myport, &etime)!=-1)
	fprintf(myoutput, "%s:%d - %ld %s\n", myhostname, myport,
		(etime.tv_usec<0)?etime.tv_sec:etime.tv_usec,
		(etime.tv_usec<0)?"sec":"usec");
      else
	fprintf(myoutput, "%s:%d - unreachable\n", myhostname,
		myport);
    }

  fclose(myinput);
  fclose(myoutput);
  
  return EXIT_SUCCESS;
}