TAP module

Hello,

i have created simple TAP module to calculate data rate.
Data rate is "all bytes"/"sum of delta-times".
Is it a good approach?

I have to process tons of trace-files
and calculate data rates (upload and download)
and time stamp of first packet.


it works like:

$tethereal -q -z ipsum,"ip.src==217.160.107.220" -r FTP.tcp.log
====================================================
Filter: ip.src==217.160.107.220

                    *** SUMMARY ***
Timestamp of first packet     : 20050619113435
Total frames                  : 186
Total bytes         (byte)    : 250084
Elapsed time        (s)       : 75,292

Average Date Rate   (kbit/s)  : 25,949
====================================================


Thank you very much.

Regards,
Mihail

[code]
// tap-iosum.c

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

#include <stdio.h>

#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#include <string.h>
#include <epan/packet_info.h>
#include <epan/packet.h>
#include <epan/tap.h>
#include <epan/emem.h>
#include <epan/stat_cmd_args.h>
#include "register.h"
#include <epan/dissectors/packet-ip.h>


typedef struct _io_sum_t {
     const char *type;
     char *filter;
         nstime_t abs_time_first;
         int frames_counter;
     struct _io_sum_item_t *item;
} io_sum_t;

typedef struct _io_sum_item_t {
     char *name;
     guint32 frames;
     guint32 bytes;
         double delta_time_accum;
} io_sum_item_t;

static int
iosum_packet(void *arg, packet_info *pinfo, epan_dissect_t *edt _U_,
const void *vip)
{
     io_sum_t *iu=arg;
     io_sum_item_t *iui;
         iu->frames_counter+=1;

         if (iu->frames_counter == 1) {
                  iu->abs_time_first = pinfo->fd->abs_ts;
         }

     iui=iu->item;

     if(!iui){
         iui=g_malloc(sizeof(io_sum_item_t));
         iu->item=iui;
         iui->frames=0;
         iui->bytes=0;
                 iui->delta_time_accum=0;
     }

     iui->frames++;
     iui->bytes+=pinfo->fd->pkt_len;
         iui->delta_time_accum+=nstime_to_sec(&pinfo->fd->del_ts);


     return 1;
}

static void
iosum_draw(void *arg)
{
     io_sum_t *iu = arg;
     io_sum_item_t *iui;

         char str_abs_time_first[60];
         char * p_abs_time_first = &str_abs_time_first[0];
         struct tm *ptr;
         ptr = localtime(&iu->abs_time_first.secs);
         strftime(p_abs_time_first, 100, "%Y%m%d%H%M%S", ptr);

         guint32 all_frames = 0;
         guint32 all_bytes = 0;
         double all_deltas = 0;

     iui=iu->item;

         if (!iui) {
                 all_frames=0;
                 all_bytes=0;
                 all_deltas=0;
         } else {
                 all_frames=iui->frames;
                 all_bytes=iui->bytes;
                 all_deltas=iui->delta_time_accum;
         }

 
printf("==================================================================\n");
         printf("Filter: %s\n",iu->filter?iu->filter:"none");
         printf("\n                     *** SUMMARY ***\n");
         if(iui) {
                 printf("Timestamp of first packet       : %s\n",
str_abs_time_first);
         }
         printf("Total frames                  : %d\n", all_frames);
         printf("Total bytes         (byte)    : %d\n", all_bytes);
         printf("Elapsed time        (s)       : %.3f\n\n", all_deltas);
         printf("Average Date Rate   (kbit/s)  : %.3f\n",
(double)(all_bytes)/(128*all_deltas) );
 
printf("===================================================================\n");
}

void
iosum_init(const char *optarg, void* userdata _U_)
{
     const char *filter=NULL;
     const char *tap_type, *tap_type_name;
     tap_packet_cb packet_func;
     io_sum_t *iu=NULL;
     GString *error_string;

         if(!strncmp(optarg,"ipsum",5)){
         if(optarg[5]==','){
             filter=optarg+6;
         } else {
             filter=NULL;
         }
         tap_type="ip";
         tap_type_name="IPv4";
         packet_func=iosum_packet;

     } else {
             fprintf(stderr,
         "tethereal: invalid \"-z ipsum[,<filter>]\" argument\n");
         exit(1);
     }


     iu=g_malloc(sizeof(io_sum_t));
     iu->item=NULL;
         iu->frames_counter = 0;
     iu->type=tap_type_name;
     if(filter){
         iu->filter=strdup(filter);
     } else {
         iu->filter=NULL;
     }

     error_string=register_tap_listener(tap_type, iu, filter, NULL,
packet_func, iosum_draw);
     if(error_string){
         if(iu->item){
             g_free(iu->item);
         }
         g_free(iu);
         fprintf(stderr,
"tethereal: Couldn't register conversations tap: %s\n",
             error_string->str);
         g_string_free(error_string, TRUE);
         exit(1);
     }

}

void
register_tap_listener_iosum(void)
{
     register_stat_cmd_arg("ipsum", iosum_init, NULL);
}

[code]