/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
 *               2002, 2003, 2004
 *	Ohio University.
 *
 * ---
 * 
 * Starting with the release of tcptrace version 6 in 2001, tcptrace
 * is licensed under the GNU General Public License (GPL).  We believe
 * that, among the available licenses, the GPL will do the best job of
 * allowing tcptrace to continue to be a valuable, freely-available
 * and well-maintained tool for the networking community.
 *
 * Previous versions of tcptrace were released under a license that
 * was much less restrictive with respect to how tcptrace could be
 * used in commercial products.  Because of this, I am willing to
 * consider alternate license arrangements as allowed in Section 10 of
 * the GNU GPL.  Before I would consider licensing tcptrace under an
 * alternate agreement with a particular individual or company,
 * however, I would have to be convinced that such an alternative
 * would be to the greater benefit of the networking community.
 * 
 * ---
 *
 * This file is part of Tcptrace.
 *
 * Tcptrace was originally written and continues to be maintained by
 * Shawn Ostermann with the help of a group of devoted students and
 * users (see the file 'THANKS').  The work on tcptrace has been made
 * possible over the years through the generous support of NASA GRC,
 * the National Science Foundation, and Sun Microsystems.
 *
 * Tcptrace is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Tcptrace is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Tcptrace (in the file 'COPYING'); if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 * 
 * Author:	Shawn Ostermann
 * 		School of Electrical Engineering and Computer Science
 * 		Ohio University
 * 		Athens, OH
 *		ostermann@cs.ohiou.edu
 *		http://www.tcptrace.org/
 */
#include "tcptrace.h"
static char const GCC_UNUSED copyright[] =
    "@(#)Copyright (c) 2004 -- Ohio University.\n";

/*
 * Kevin Lahey (kml@patheticgeek.net)
 */

static char const GCC_UNUSED rcsid[] =
    "@(#)$Header: /usr/local/cvs/tcptrace/ns.c,v 1.18 2003/11/19 14:38:04 sdo Exp $";


/* 
 * ns.c - ns specific file reading stuff
 */



#ifdef GROK_NS

/* Defining SYS_STDIN which is fp for Windows and stdin for all other systems */
#ifdef __WIN32
static FILE *fp;
#define SYS_STDIN fp
#else
#define SYS_STDIN stdin
#endif /* __WIN32 */

/* static buffers for reading */
static struct ether_header *pep;
static int *pip_buf;
static struct ip *ipb;
static struct tcphdr *tcpb;

/* for debugging */
static unsigned linenum;

/* return the next packet header */
/* currently only works for ETHERNET */
static int
pread_ns(
    struct timeval	*ptime,
    int		 	*plen,
    int		 	*ptlen,
    void		**pphys,
    int			*pphystype,
    struct ip		**ppip,
    void		**pplast)
{
    static int packlen = 0;
    double c, d, e;

    while (1) {
	/* read the packet info */

	char tt;
	double timestamp;
	int junk;
	char type[16];
	char flags[16];
	int iteration;
	int seq;
	int is_ack;
	int is_tcp;
	int rlen;
	char myline[128];
	char *isend;

	++linenum;

	isend = fgets(myline, 128, SYS_STDIN);
	if (isend == NULL) {  // end of file
		return(0);
	}
	/* correct NS output line would have 14 fields: */
	rlen = sscanf(myline, "%c %lg %d %d %s %d %s %d %d.%hu %d.%hu %d %hu",
		      &tt,
		      &timestamp,
		      &junk,
		      &junk,
		      type,
		      plen,
		      flags,
		      &iteration,
		      &ipb->ip_src.s_addr,
		      &tcpb->th_sport,
		      &ipb->ip_dst.s_addr,
		      &tcpb->th_dport,
		      &seq,
		      &ipb->ip_id);

	/* if we can't match all 14 fields, we give up on the file */
	if (rlen != 14 && rlen != 18) {
	    fprintf(stderr,"Bad NS packet header in line %u only [%d] arguments can be matched expected 14 or 18 \n", linenum, rlen);
	    return(0);
	}

        // find out who put in this line of code, because I'd love
        // to know what their reasoning was
	//tcpb->th_sport = tcpb->th_dport = iteration;

	is_tcp = strcmp(type, "tcp") == 0;
	is_ack = strcmp(type, "ack") == 0;

	/* if it's not a TCP data segment or ACK, discard and try again */
	if (!is_tcp && !is_ack)
	    continue;
	
	if ((!ns_hdrs && is_tcp) || (ns_hdrs && packlen ==0))
		*plen = *plen + sizeof(struct ip) + sizeof(struct tcphdr);
	
	if (packlen == 0 && is_tcp)
		packlen = *plen - sizeof(struct ip) - sizeof(struct tcphdr);
	
	if (ns_hdrs && is_tcp)
		packlen = *plen- sizeof(struct ip) - sizeof(struct tcphdr);

	if (is_ack) /* this is explicitly for SACK that creates packets > 40 Bytes*/
	*plen = 40;
	
	ipb->ip_len = htons(*plen);

	if (is_tcp) {
	    tcpb->th_seq = htonl(packlen * seq);
	    tcpb->th_ack = 0;
	} else {
	    tcpb->th_seq = 0;
	    tcpb->th_ack = htonl(packlen * (seq + 1));
	}

	/* make up a reasonable IPv4 packet header */
#ifdef __VMS
	ipb->ip_vhl = 0x0405; /* no options, normal length of 20 */
#else
	ipb->ip_hl = 5; /* no options, normal length of 20 */
	ipb->ip_v = 4;  /* IPv4 */
#endif
	
	ipb->ip_tos = 0;
	ipb->ip_off = 0;
	ipb->ip_ttl = 64;  /* nice round number */
	ipb->ip_p = 6;     /* TCP */
	ipb->ip_sum = 0;   /* IP checksum, hope it doesn't get checked! */
	ipb->ip_id = htons(ipb->ip_id);

	/* is the transport "ECN-Capable"? */
	if (strchr(flags, 'N') != NULL)
	    ipb->ip_tos |= IPTOS_ECT;

	/* was the "Experienced Congestion" bit set? */
	if (strchr(flags, 'E') != NULL)
	    ipb->ip_tos |= IPTOS_CE;

	/* make up a reasonable TCP segment header */
#ifdef __VMS
	tcpb->th_xoff = 0x50;  /* no options, normal length of 20 */
#else
	tcpb->th_off = 5;  /* no options, normal length of 20 */
	tcpb->th_x2 = 0;
#endif
	tcpb->th_flags = TH_ACK; /* sdo: what about first SYN?? */
	tcpb->th_sum = 0;
	tcpb->th_urp = 0;
	tcpb->th_win = htons(65535);

	/* x2 *was* reserved, now used for ECN bits */

	if (strchr(flags, 'C') != NULL)
#ifdef __VMS
	    tcpb->th_xoff |= TH_ECN_ECHO;
#else
	    tcpb->th_x2 |= TH_ECN_ECHO;
#endif
	if (strchr(flags, 'A') != NULL)
#ifdef __VMS
	    tcpb->th_xoff |= TH_CWR;
#else
	    tcpb->th_x2 |= TH_CWR;
#endif

	/* convert floating point timestamp to (tv_sec,tv_usec) */
	c = floor(timestamp);
	ptime->tv_sec  = c;
	d = timestamp - (double) ptime->tv_sec;
	e = d * 1000000.0;
	ptime->tv_usec = e;

	*ptlen = *plen;

	*ppip  = (struct ip *) pip_buf;
	*pplast = (char *)pip_buf + *plen;
	*pphys  = pep;
	*pphystype = PHYS_ETHER;

/*
  printf("timestamp %g, type %s, plen %d, seq %d, id %d\n",
  timestamp, type, *plen, seq, ipb->ip_id);
*/
	return(1);
    }
}

int pread_ns_fulltcp(
    struct timeval	*ptime,
    int		 	*plen,
    int		 	*ptlen,
    void		**pphys,
    int			*pphystype,
    struct ip		**ppip,
    void		**pplast)
{
    double c, d, e;
    while (1) {
	/* read the packet info */

	char tt;
	double timestamp;
	int junk;
        unsigned short junkshort;
	char type[16];
	char flags[16];
	int iteration;
	int seqno;
	int ackno;
	int hdrlen;
	int is_ack;
	int is_tcp;
	int pflags;
	int rlen;
	char myline[128];
	char *isend;

	++linenum;

	isend = fgets(myline, 128, SYS_STDIN);
	if (isend == NULL) {  // end of file
		return 0;
	}
	/* correct NS output line would have 14 fields if show_tcphdr_ is 0: */
	/* For Full TCP this changes to 18 fields when show_tcp is 1*/
	rlen = sscanf(myline, "%c %lg %d %d %s %d %s %d %d.%hu %d.%hu %d %hu %d 0x%x %u %hu",
		      &tt,
		      &timestamp,
		      &junk,
		      &junk,
		      type,
		      plen,
		      flags,
		      &iteration,
		      &ipb->ip_src.s_addr,
		      &tcpb->th_sport,
		      &ipb->ip_dst.s_addr,
		      &tcpb->th_dport,
		      &seqno,
			  &ipb->ip_id,
			  &ackno,
			  &pflags,
			  &hdrlen,
			  &junkshort);

	/* if we can't match all 18 fields, we give up on the file */
	if (rlen != 18) {
		fprintf(stderr, "\"%s\"\n", myline);
	    fprintf(stderr,"Bad NS packet header in line %u only [%d] arguments can be matched expected 14 or 18 \n", linenum, rlen);
	    fprintf(stderr,"Is this a Full Tcp Header?\n");
	    return(0);
	}

	//tcpb->th_sport = tcpb->th_dport = iteration;
	is_tcp = strcmp(type, "tcp") == 0;
	is_ack = strcmp(type, "ack") == 0;
	
	/* if it's not a TCP data segment or ACK, discard and try again */
	if (!is_tcp && !is_ack)
	    continue;
	
	/* we have biger header than 40 Bytes (SACK?) */
	if (hdrlen > sizeof(struct ip) + sizeof(struct tcphdr)){ 
		*plen -= (hdrlen - (sizeof(struct ip) + sizeof(struct tcphdr)));
	}

	ipb->ip_len = htons(*plen);

	tcpb->th_seq = htonl(seqno);
	tcpb->th_ack = htonl(ackno);

	/* make up a reasonable IPv4 packet header */
	ipb->ip_hl = 5; /* no options, normal length of 20 */
	ipb->ip_v = 4;  /* IPv4 */
	ipb->ip_tos = 0;
	ipb->ip_off = 0;
	ipb->ip_ttl = 64;  /* nice round number */
	ipb->ip_p = 6;     /* TCP */
	ipb->ip_sum = 0;   /* IP checksum, hope it doesn't get checked! */
	ipb->ip_id = ipb->ip_id;

	/* is the transport "ECN-Capable"? */
	if (strchr(flags, 'N') != NULL)
	    ipb->ip_tos |= IPTOS_ECT;

	/* was the "Experienced Congestion" bit set? */
	if (strchr(flags, 'E') != NULL)
	    ipb->ip_tos |= IPTOS_CE;

	/* make up a reasonable TCP segment header */
	tcpb->th_off = 5;  /* no options, normal length of 20 */
	tcpb->th_flags = pflags; /* sdo: what about first SYN?? */
	tcpb->th_x2 = 0;
	tcpb->th_sum = 0;
	tcpb->th_urp = 0;
	tcpb->th_win = htons(65535);

	/* x2 *was* reserved, now used for ECN bits */

	if (strchr(flags, 'C') != NULL)
	    tcpb->th_x2 |= TH_ECN_ECHO;
	if (strchr(flags, 'A') != NULL)
	    tcpb->th_x2 |= TH_CWR;

	/* convert floating point timestamp to (tv_sec,tv_usec) */
	c = floor(timestamp);
	ptime->tv_sec  = c;
	d = timestamp - (double) ptime->tv_sec;
	e = d * 1000000.0;
	ptime->tv_usec = e;

	*ptlen = *plen;

	*ppip  = (struct ip *) pip_buf;
	*pplast = (char *)pip_buf + *plen;
	*pphys  = pep;
	*pphystype = PHYS_ETHER;


  /* printf("timestamp %g, type %s, plen %d, seq %d, id %d, ack %d, 0x%x %d \n",
  timestamp, type, *plen, seqno, ipb->ip_id,ackno,pflags,hdrlen); */


	return(1);
    }

return(0);
}


/*
 * is_ns()   is the input file in ns format??
 */
pread_f *is_ns(char *filename)
{
    int rlen;
    char tt;
    int junk;
    double junkd;
    char junks[20];
    unsigned short junkshort;
    int hdrlen = 0;
    int pflags = 0;
    char myline[128];  // read into this line and then parse for values

#ifdef __WIN32
    if((fp = fopen(filename, "r")) == NULL) {
       perror(filename);
       exit(-1);
    }
#endif /* __WIN32 */   

    fgets(myline, 128, SYS_STDIN);
    rlen = sscanf(myline, 
		  "%c %lg %d %d %s %d %s %d %d.%hu %d.%hu %d %hu %d 0x%x %u %hu", 
		  &tt, &junkd, &junk, &junk, (char *)&junks, &junk, 
		  (char *)&junks, &junk, &junk, &junkshort, &junk, 
		  &junkshort, &junk, &junkshort, &junk, &pflags, &hdrlen, 
		  &junkshort);

    if ((rlen = getc(SYS_STDIN)) == EOF) {
	return(NULL);
    } else {
	    if (ungetc(rlen, SYS_STDIN) == EOF)
		    return NULL;
    }

    switch (tt) {
      case '+':
      case '-':
      case 'h':
      case 'r':
      case 'd':
	break;
      default:
	return(NULL);
    }

    /* OK, it's mine.  Init some stuff */
    pep = MallocZ(sizeof(struct ether_header));
    pip_buf = MallocZ(IP_MAXPACKET);
    
    ipb = (struct ip *) pip_buf;
    tcpb = (struct tcphdr *) (ipb + 1);

    /* Set up the stuff that shouldn't change */
    pep->ether_type = ETHERTYPE_IP;

    /* init line count (we might be called several times, must be done here) */
    linenum = 0;
	/* Lets check if it is FullTCP or not*/
	if (hdrlen || pflags){ /*it is FullTCP */
/*		printf("Full TCP \n"); */
		rewind(SYS_STDIN);
		return(pread_ns_fulltcp);
	}
	else{ /*Regular TCP (with or without tcpheaders activated */
    	return(pread_ns); 
	}
}
#endif /* GROK_NS */