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pcap_filter サンプル
[プログラムでWinPcapを使用する方法]


/*
 * Copyright (c) 1999 - 2002
 *  Politecnico di Torino.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the Politecnico
 * di Torino, and its contributors.'' Neither the name of
 * the University 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 WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <stdlib.h>
#include <stdio.h>

#include <pcap.h>

#define MAX_PRINT 80
#define MAX_LINE 16


void dispatcher_handler(u_char *, 
const struct pcap_pkthdr *, const u_char *);
void usage();

void main(int argc, char **argv) {
pcap_t *fp;
char error[PCAP_ERRBUF_SIZE];
char *device=NULL;
char *ifilename=NULL;
char *ofilename=NULL;
char *filter=NULL;
int i=0;
pcap_dumper_t *dumpfile;
struct bpf_program fcode;
bpf_u_int32 SubNet,NetMask;

if (argc == 1)
{
usage();
return;
}

for(i=1;i<argc;i+=2){

switch (argv[i] [1])
{

case 'i':
{
device=argv[i+1];
};
break;

case 'f':
{
ifilename=argv[i+1];
};
break;

case 'o':
{
ofilename=argv[i+1];
};
break;

case 'p':
{
filter=argv[i+1];
};
break;


}

}

//open a capture from the network if (device != NULL){
if ( (fp= pcap_open_live(device, 1514, 1, 20, error) ) == NULL)
{
fprintf(stderr,"\nUnable to open the adapter.\n");
return;
}
}
//open a capture from file else if (ifilename != NULL){
if ( (fp = pcap_open_offline(ifilename, NULL) ) == NULL)
{
fprintf(stderr,"\nUnable to find input file.\n");
return;
}
}
else usage();

if(filter!=NULL){

//obtain the subnet if(device!=NULL){
if(pcap_lookupnet(device, &SubNet, &NetMask, error)<0){
fprintf(stderr,"\nUnable to obtain the netmask.\n");
return;
}
}
else NetMask=0xffffff; //If reading from file, we suppose to be in a C class network //compile the filter if(pcap_compile(fp, &fcode, filter, 1, NetMask)<0){
fprintf(stderr,"\nError compiling filter: wrong syntax.\n");
return;
}

//set the filter if(pcap_setfilter(fp, &fcode)<0){
fprintf(stderr,"\nError setting the filter\n");
return;
}

}

//open the dump file if (ofilename != NULL){
dumpfile=pcap_dump_open(fp, ofilename);
if(dumpfile==NULL){
fprintf(stderr,"\nError opening output file\n");
return;
}
}
else usage();

//start the capture pcap_loop(fp, 0, dispatcher_handler, (unsigned char *)dumpfile);

}


//Callback function called by libpcap for every incoming packet void dispatcher_handler(u_char *dumpfile,
const struct pcap_pkthdr *header, const u_char *pkt_data)
{
u_int i=0;

//save the packet on the dump file pcap_dump(dumpfile,header,pkt_data);

}


void usage()
{

printf("\npf - generic packet filter.\nWritten by Loris Degioanni (loris@netgroup-serv.polito.it).");
printf("\nUsage:\npf [-i interface] | [-f input_file_name] -o output_file_name -p packet_filter\n\n");
exit(0);
}

documentation. Copyright (c)2002-2003 Politecnico di Torino.
2005 translated by Telebusiness,Inc.
 All rights reserved.