source: examples/protocol/protocol.c @ c837874

/*
 * This file is part of libtrace
 *
 * Copyright (c) 2004 The University of Waikato, Hamilton, New Zealand.
 * Authors: Daniel Lawson 
 *          Perry Lorier 
 *          
 * All rights reserved.
 *
 * This code has been developed by the University of Waikato WAND 
 * research group. For further information please see http://www.wand.net.nz/
 *
 * libtrace 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.
 *
 * libtrace 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 libtrace; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id$
 *
 */

#include <stdio.h> /* printf */
#include <netinet/in.h> /* ntohs */
#include <netdb.h>
#include "dagformat.h"
#include <getopt.h>

#include <stdlib.h>
#include <string.h>

#include <errno.h>

#include <linux/types.h>
//#include <linux/linkage.h>
//#define  access_ok(type,addr,size) 1

static inline unsigned short ip_fast_csum(unsigned char * iph,
                                          unsigned int ihl) {
        unsigned int sum;

        __asm__ __volatile__("
            movl (%1), %0
            subl $4, %2
            jbe 2f
            addl 4(%1), %0
            adcl 8(%1), %0
            adcl 12(%1), %0
1:          adcl 16(%1), %0
            lea 4(%1), %1
            decl %2
            jne 1b
            adcl $0, %0
            movl %0, %2
            shrl $16, %0
            addw %w2, %w0
            adcl $0, %0
            notl %0
2:
            "
        /* Since the input registers which are loaded with iph and ipl
           are modified, we must also specify them as outputs, or gcc
           will assume they contain their original values. */
        : "=r" (sum), "=r" (iph), "=r" (ihl)
        : "1" (iph), "2" (ihl));
        return(sum);
}

#define  IN_CHKSUM(IP)  ip_fast_csum((unsigned char *)(IP), 5)


#include "libtrace.h"

struct libtrace_t *trace;
struct libtrace_filter_t *filter;

char *buffer[4096];
uint64_t badchksum = 0;
char *uri = 0;
char *filterstring = 0;

int do_cksum = 0;
int do_w_cksum = 0;
static void usage();
static void parse_cmdline(int argc, char **argv);

int main(int argc, char **argv) {

        struct libtrace_ip *ipptr = 0;
        
        int status; // need to pass to rtclient_read_packet
        int psize;

        parse_cmdline(argc,argv);

        // create an rtclient to hostname, on the default port
        trace = create_trace(uri);
        if (filterstring) {
                filter = libtrace_bpf_setfilter(filterstring);
        }

        for (;;) {
                if ((psize = libtrace_read_packet(trace, buffer,4096, &status)) <= 0) {
                        // terminate
                        break;
                }
                if (filter) {
                        if (!libtrace_bpf_filter(trace, filter, buffer, 4096)) {
                        continue;
                        }
                }
                ipptr = get_ip(trace,buffer,4096);

                if (ipptr) {
                        if(do_cksum && IN_CHKSUM(ipptr)) {
                                badchksum ++;
                        } else if (do_w_cksum && ipptr->ip_sum) {
                                badchksum ++;
                        } else {
                                printf("%d:%d\n",ipptr->ip_p,get_link_type(trace,buffer,4096));
                        }
                }
        }
        if (do_cksum || do_w_cksum) {
                printf("Bad checksums seen: %llu\n",badchksum);
        }
        destroy_trace(trace);
        return 0;
}


static void usage(char *prog) {
        printf("usage: %s [-h] [-c | -w] [-u <uri>] [-f <filterstring>]\n",prog);
        printf("        -h              this help message\n");
        printf("        -c              perform ip checksum test\n");
        printf("        -w              check WDCAPd ip checksum value\n");
        printf("        -u uri          uri to connect to\n");
        printf("        -f filterstring BPF filterstring to apply\n");
        printf("\n");
        printf(" The use of -c and -w are exclusive: -c is used for normal traces, while -w applies to traces taken from the Waikato Capture point\n");
}

static void parse_cmdline(int argc, char **argv){
        int opt;
        if (argc == 1) {
                usage(argv[0]);
                exit(0);
        }
        
        while ((opt = getopt(argc,argv, "hcwu:f:")) != EOF) {
                switch(opt) {
                        case 'h':
                                usage(argv[0]);
                                exit(0);
                        case 'c':
                                do_cksum = 1;
                                break;
                        case 'w':
                                do_w_cksum = 1;
                                break;
                        case 'u':
                                uri = strdup(optarg);
                                break;
                        case 'f':
                                filterstring = strdup(optarg);
                                break;
                        default:
                                usage(argv[0]);
                                exit(0);
                }

        }

        if (do_cksum && do_w_cksum) {
                usage(argv[0]);
                exit(0);
        }

}