source: tools/tracediff/tracediff.c @ f68d5b8

/* Tool that compares two traces and outputs any packets that do not match
 * between the two
 *
 * Author: Shane Alcock
 */

#include "libtrace.h"
#include <stdio.h>
#include <assert.h>
#include <getopt.h>
#include <string.h>
#include <stdlib.h>

#include "libpacketdump.h"

uint32_t max_diff = 0;
uint32_t dumped_diff = 0;

/* Compares the two provided packets. If the packets differ in any fashion,
 * both will be dumped to standard output using libpacketdump followed by a
 * line of asterisks.
 *
 * Note that only the contents of the packet are compared; the framing provided
 * by the trace format, e.g. the ERF or PCAP header, is not examined.
 */
void per_packet(libtrace_packet_t *a, libtrace_packet_t *b)
{
        char *buf_a, *buf_b;
        libtrace_linktype_t lt;
        uint32_t rem_a, rem_b;


        buf_a = trace_get_packet_buffer(a, &lt, &rem_a);
        buf_b = trace_get_packet_buffer(b, &lt, &rem_b);

        if (rem_a > trace_get_wire_length(a))
                rem_a = trace_get_wire_length(a);
        if (rem_b > trace_get_wire_length(b))
                rem_b = trace_get_wire_length(b);
        

        if (!buf_a && !buf_b)
                return;

        if (!buf_a || !buf_b) {
                trace_dump_packet(a);
                trace_dump_packet(b);
                printf("****************\n");
                dumped_diff ++;
                return;
        }
                

        if (rem_a == 0 || rem_b == 0)
                return;

        if (rem_a != rem_b) {
                trace_dump_packet(a);
                trace_dump_packet(b);
                printf("****************\n");
                dumped_diff ++;
                return;
        }

        /* This is not exactly going to be snappy, but it's the easiest way
         * to look for differences */
        if (memcmp(buf_a, buf_b, rem_a) != 0) {
                trace_dump_packet(a);
                trace_dump_packet(b);
                printf("****************\n");
                dumped_diff ++;
        }

}

void usage(char *prog) {
        printf("Usage instructions for %s\n\n", prog);
        printf("\t%s [options] traceA traceB\n\n", prog);
        printf("Supported options:\n");
        printf("\t-m <max>   Stop after <max> differences have been reported\n");

        
        return;

}

int main(int argc, char *argv[])
{
        libtrace_t *trace[2];
        libtrace_packet_t *packet[2];
        int opt, i;
        
        if (argc<2) {
                usage(argv[0]);
                return -1;
        }

        while ((opt = getopt(argc, argv, "m:")) != EOF) {
                switch (opt) {
                        case 'm':
                                if (atoi(optarg) < 0) {
                                        fprintf(stderr, "-m option must not be negative - ignoring\n");
                                } else {
                                        max_diff = (uint32_t) atoi(optarg);
                                }
                                break;
                        default:
                                usage(argv[0]);
                }
        }

        if (optind + 2 > argc) {
                usage(argv[0]);
                return -1;
        }
        packet[0] = trace_create_packet();
        packet[1] = trace_create_packet();

        trace[0] = trace_create(argv[optind++]);

        if (trace_is_err(trace[0])) {
                trace_perror(trace[0],"Opening trace file");
                return -1;
        }

        if (trace_start(trace[0])) {
                trace_perror(trace[0],"Starting trace");
                trace_destroy(trace[0]);
                return -1;
        }

        trace[1] = trace_create(argv[optind++]);

        if (trace_is_err(trace[1])) {
                trace_perror(trace[1],"Opening trace file");
                return -1;
        }

        if (trace_start(trace[1])) {
                trace_perror(trace[1],"Starting trace");
                trace_destroy(trace[1]);
                return -1;
        }

        while (trace_read_packet(trace[0], packet[0]) > 0 &&
                        trace_read_packet(trace[1], packet[1]) > 0) {

                per_packet(packet[0], packet[1]);

                if (max_diff > 0 && dumped_diff >= max_diff)
                        break;

        }

        if (trace_is_err(trace[0])) {
                trace_perror(trace[0],"Reading packets");
                trace_destroy(trace[0]);
                return -1;
        }
        
        if (trace_is_err(trace[1])) {
                trace_perror(trace[1],"Reading packets");
                trace_destroy(trace[1]);
                return -1;
        }

        trace_destroy(trace[0]);
        trace_destroy(trace[1]);
                
        trace_destroy_packet(packet[0]);
        trace_destroy_packet(packet[1]);
        
        if (dumped_diff == 0)
                return 0;
        else
                return 1;
}