/*
  tcpreplay.c

  Matt Undy <mundy@anzen.com>
  
  Copyright (c) 1999 Anzen Computing. All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
  3. All advertising materials mentioning features or use of this software
     must display the following acknowledgement:
        This product includes software developed by Anzen Computing, Inc.
  4. Neither the name of Anzen Computing, Inc. nor the names of its
     contributors may be used to endorse or promote products derived
     from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  Notes:
  The performance of paced modes could be increased somewhat by
  estimating sleep time and only checking against the RTC ocasionally,
  although this would also result in a less precise data rate,
  especially on machines with an imprecise usleep().
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdio.h>
#include <stdlib.h>
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#include <pcap.h>
#include <libnet.h>

#define TCPREPLAY_VERSION	"1.0.1"

#define PACE 1            /*0b01*/
#define RATE 2            /*0b10*/
#define TIME_GT(x,y) (x tv_sec>y tv_sec||(x tv_sec==y tv_sec&&x tv_usec>y tv_usec))
#define TIME_LT(x,y) (x tv_sec<y tv_sec||(x tv_sec==y tv_sec&&x tv_usec<y tv_usec))
#define TIME_ASSIGN(x,y)  x tv_sec=y tv_sec; x tv_usec=y tv_usec;
#define PRINT_TIMEVAL(x) fprintf(stderr, " tv_sec=%li tv_usec=%li\n",x tv_sec, x tv_usec);

typedef struct timeval time_struct;
extern int errno;
int failed_writes, first_pkt,older_pkts;
int pkts_sent;
long long bytes_sent;
int iterrations;
int mode;
int rate;
int debug;
float multiplier;
struct timeval lasttime, lastpkt, behind_time, starttime_struc,
  startpkt_struct, last_dpkt, starttime, pkttime_struct;
int caplen;
int iterations;
char * interface;

void usage(){
  fprintf(stderr, "Version: " TCPREPLAY_VERSION "\nUsage: tcpreplay "
	  "[-i interface] [-l loops] [-m multiplier] [-r rate] <file>\n");
  exit (1);
}

/* we aren't checking for overflow here.  if it happens we have run
   into the 2038 problem and the whole time handling is broken (or a bug). */

void addtime(time_struct * op1,time_struct *  op2,time_struct * result)
{
  result->tv_usec = op1->tv_usec+op2->tv_usec;
  if (result->tv_usec > 999999) {
    result->tv_usec -= 1000000;
    op1->tv_sec++;
  }
  result->tv_sec = op1->tv_sec+op2->tv_sec;
}

/*
  if op1>op2, return op1-op2 and 0
  if op1<op2, return |op1-op2| and 1
              (return a negative # with the sign bit in the return int)
  if op2>op1, subtract op2 from op1 and set return int
*/

int subtime(time_struct * op1, time_struct * op2, time_struct * result)
{
  int borrow=0;     
  int sign=0;
  time_struct * temp_time;
  
  if (TIME_LT(op1->, op2->)) {
    sign = 1;
    temp_time = op1;
    op1 = op2;
    op2 = temp_time;
  }
  if (op1->tv_usec >= op2->tv_usec) {
    result->tv_usec = op1->tv_usec-op2->tv_usec;
  }
  else {
    result->tv_usec = (op1->tv_usec+1000000)-op2->tv_usec;
    borrow = 1;
  }
  result->tv_sec = (op1->tv_sec-op2->tv_sec)-borrow;
  
  return sign;
}

void divtime(time_struct * num, float denom) {
  num->tv_sec = num->tv_sec/denom;
  num->tv_usec = num->tv_usec/denom;
}

void write_packet(u_char * user,struct pcap_pkthdr* pcap_hdr, u_char * data)
{
  int write_status = -1;
  float sec;
  struct timeval now, dtime, dpkt, sleeptime; 

 
  if (mode) {
#if HAVE_GETTIMEOFDAY 
    gettimeofday(&now,NULL);
#endif
    iterations++;
#ifdef DEBUG
    if ((!(iterations %99))&&debug>0) {
      fprintf(stderr, "\nELAPSED TIME %lu sec %li usec\n\n",
	     now.tv_sec-starttime_struc.tv_sec,
	     now.tv_usec - starttime_struc.tv_usec);
      fprintf(stderr, "\nELAPSED PACKET TIME %lu sec %li usec\n\n",
	     pcap_hdr->ts.tv_sec - startpkt_struct.tv_sec,
	     pcap_hdr->ts.tv_usec - startpkt_struct.tv_usec); 
    }
#endif
    if (first_pkt) {
      first_pkt = 0;
      TIME_ASSIGN(starttime_struc., now.);
      TIME_ASSIGN(lastpkt., pcap_hdr->ts.);
      TIME_ASSIGN(startpkt_struct., pcap_hdr->ts.);

    }
    if (subtime(&now, &starttime_struc, &dtime)) {
      fprintf(stderr, "The RTC has decreased since last read (or someone multithreaded this wrong)\n");
      /*if it is earlier than the last time we executed this loop,
        something is very wrong*/
      abort();
    }
    if (mode & PACE) {
      if (subtime(&pcap_hdr->ts, &lastpkt, &dpkt)) {
        /*Uncomment this if you want to stop on out of order packets
          in the dump file*/
        /*fprintf(stderr, "packets in pcap file not in increasing time of arrival\n");
          abort();*/
        older_pkts++;
      }
      else {
        divtime(&dpkt, multiplier);
        addtime(&dpkt, &pkttime_struct, &pkttime_struct);
      }
#ifdef DEBUG
      if (debug > 2) {
        fprintf(stderr, "dtime: ");
        PRINT_TIMEVAL(dtime.);
        fprintf(stderr, "pkttime_struct: ");
        PRINT_TIMEVAL(pkttime_struct.);
      }
#endif
    }
    if (mode & RATE) {
      /*calculate time packet should take, add to total packet time. */
      sec = (float)pcap_hdr->caplen / (float)rate;
      dpkt.tv_sec = sec;
      dpkt.tv_usec = (sec - dpkt.tv_sec) * 1000000;
#ifdef DEBUG
      if (debug > 2) {
        fprintf(stderr, "dpkt:");
        PRINT_TIMEVAL(dpkt.);
      }
#endif
      addtime(&dpkt, &pkttime_struct, &pkttime_struct);
#ifdef DEBUG
      if (debug > 2) {
        fprintf(stderr, "pkttime_struct: ");
        PRINT_TIMEVAL(pkttime_struct.);
      }
#endif
    }
    if (subtime(&dtime, &pkttime_struct, &sleeptime)) {
      /*we are ahead by pkttime if true*/
#ifdef DEBUG
      if (debug > 2) {
        fprintf(stderr, "sleeptime: ");
        PRINT_TIMEVAL(sleeptime.);
      }
#endif
      sleep(sleeptime.tv_sec);
      usleep(sleeptime.tv_usec);
    }
    TIME_ASSIGN(lastpkt., pcap_hdr->ts.); 
  }

  while (write_status < 0) {
    write_status = write_link_layer((struct link_int *)user, interface,
				    data,pcap_hdr->caplen);
#ifdef DEBUG
    if (debug > 1) {
      fprintf(stderr, "write_status = %i\n", write_status);
    }
#endif
    if (write_status < 0) {
      /*if errno =  = 55(ENOBUFS) loop, otherwise break*/

      if (errno != ENOBUFS) {
	fprintf(stderr, "errno = %i\n", errno);
	perror("pcap_inject");
	exit(1);
      }
      else {
	failed_writes++;
      }
    }
  }
  bytes_sent += write_status;
  pkts_sent++;
}
int main(int argc, char * argv[])
{
  pcap_t * in_file;
  struct link_int * write_if;
  float Mrate = 0;
  double starttime_local, startusec;
  char ebuf[256];
  struct timeval tp;
  extern char *optarg;
  extern int optind;
  int ch, iterrated,files = 0;
  char * name = NULL;
  int stdinput  = 0;
  debug = 0;
  iterrations = 1;
  mode = 0;
  interface = NULL;

  while ((ch = getopt(argc, argv, "i:l:r:m:h")) != -1)
    switch(ch) {
    case 'd':
      debug++;
      break;
    case 'm':
      multiplier = atof(optarg);
      mode = mode | PACE;
      break;
    case 'r':
      mode = mode | RATE;
      Mrate = atof(optarg);
      rate = (Mrate * (1024 * 1024)) / 8;
      break;
    case 'l':
      iterrations = atoi(optarg);
      break;
    case 'i':
      interface = optarg;
      break;
    case 'h':
      usage();
      break;
    default:
      usage();
    }
  
  if ((mode & PACE) && (mode & RATE)) {
    usage();
  }
  if ((mode & PACE) && multiplier == 0) {
    fprintf(stderr, "invalid pace multiplier - use a nonzero multiplier\n");
    usage();
  }
  if ((mode & RATE) && (Mrate == 0)) {
    fprintf(stderr, "invalid sending rate - use a nonzero rate\n");
    usage();
  }
  if (interface == NULL) {
    if (!(interface = pcap_lookupdev(ebuf))) {
      fprintf(stderr, "can't determine default interface: %s\n", ebuf);
      exit(1);
    }
  }
  
  iterations = 0;
  older_pkts = 0;
#if HAVE_GETTIMEOFDAY
  gettimeofday(&tp,NULL);
#endif
  /*if you don't have gettimeofday, you will have to add the appropriate 
    syscall for your system*/
  starttime_local = tp.tv_sec;
  startusec = tp.tv_usec;
  failed_writes  = 0;
  pkts_sent = 0;
  bytes_sent = 0;
  write_if = open_link_interface(interface,ebuf);
  if (write_if <= 0) {
    fprintf(stderr, "output i/f: %s\n",ebuf);
    exit(1);
  }
  /*need to account for no args*/

  if (argc == optind) {
    stdinput = 1;
  }
  for (files=0;files < argc-optind || stdinput;files++) {
    if (stdinput) {
      name = malloc(4);
      strcpy(name,"-");
    }
    else {
      name = argv[files+optind];
    }
    for (iterrated = 0; iterrated < iterrations; iterrated++){
      first_pkt = 1;
#if HAVE_GETTIMEOFDAY
      gettimeofday(&tp,NULL);
#endif
      pkttime_struct.tv_sec = 0;
      pkttime_struct.tv_usec = 0;
      lasttime.tv_sec = tp.tv_sec;
      lasttime.tv_usec = tp.tv_usec;
      in_file = pcap_open_offline(name, ebuf);
      if (!in_file) {
        fprintf(stderr, "Error opening %s for reading\n",argv[1]);
        fprintf(stderr, "in_file: %s\n",ebuf);
        exit (1);
      }
      if (pcap_dispatch(in_file, 0,(void *)&write_packet,
			(u_char *) write_if) == -1) {
	pcap_perror(in_file, argv[1]);
      }
      pcap_close(in_file);
    }
    stdinput = 0;
  }
  if (failed_writes) {
    fprintf(stderr, "%i write attempts failed from full buffers and were repeated\n", failed_writes);
  }
  if (older_pkts) {
    fprintf(stderr, "%i packet delays removed because they were out of order\n", older_pkts);
  }
  fprintf(stderr, "%i packets sucessfully sent", pkts_sent);
#if HAVE_GETTIMEOFDAY
  gettimeofday(&tp, NULL);
#endif
  fprintf(stderr, " in %f seconds(%f packets per second)\n",
         (tp.tv_sec - starttime_local + ((tp.tv_usec - startusec) / 1000000)),
         (pkts_sent / ((tp.tv_sec - starttime_local) * 1000000 +
		       ((tp.tv_usec - startusec)))) * 1000000);
  fprintf(stderr, "%lld bytes sucessfully sent", bytes_sent);
  
  fprintf(stderr, "(%f bytes per second\n",
         (bytes_sent / ((tp.tv_sec - starttime_local) * 1000000 +
			((tp.tv_usec - startusec)))) * 1000000);
  fprintf(stderr, "%f megabits per second)\n",
	  (((bytes_sent / ((tp.tv_sec - starttime_local) * 1000000 +
			   ((tp.tv_usec-startusec)))) * 1000000) * 8) /
	  (1024 * 1024));  
  exit(0);
}