105 lines
2.7 KiB
C
105 lines
2.7 KiB
C
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#include "pcap.h"
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/* prototype of the packet handler */
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void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data);
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int main(int argc, char **argv)
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{
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pcap_if_t *alldevs;
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pcap_if_t *d;
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int inum;
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int i=0;
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pcap_t *adhandle;
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char errbuf[PCAP_ERRBUF_SIZE];
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pcap_dumper_t *dumpfile;
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/* Check command line */
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if(argc != 2)
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{
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printf("usage: %s filename", argv[0]);
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return -1;
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}
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/* Retrieve the device list on the local machine */
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if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
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{
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fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
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exit(1);
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}
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/* Print the list */
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for(d=alldevs; d; d=d->next)
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{
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printf("%d. %s", ++i, d->name);
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if (d->description)
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printf(" (%s)\n", d->description);
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else
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printf(" (No description available)\n");
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}
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if(i==0)
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{
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printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
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return -1;
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}
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printf("Enter the interface number (1-%d):",i);
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scanf_s("%d", &inum);
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if(inum < 1 || inum > i)
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{
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printf("\nInterface number out of range.\n");
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/* Free the device list */
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pcap_freealldevs(alldevs);
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return -1;
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}
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/* Jump to the selected adapter */
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for(d=alldevs, i=0; i< inum-1 ;d=d->next, i++);
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/* Open the device */
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if ( (adhandle= pcap_open(d->name, // name of the device
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65536, // portion of the packet to capture
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// 65536 guarantees that the whole packet will be captured on all the link layers
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PCAP_OPENFLAG_PROMISCUOUS, // promiscuous mode
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1000, // read timeout
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NULL, // authentication on the remote machine
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errbuf // error buffer
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) ) == NULL)
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{
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fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n", d->name);
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/* Free the device list */
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pcap_freealldevs(alldevs);
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return -1;
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}
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/* Open the dump file */
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dumpfile = pcap_dump_open(adhandle, argv[1]);
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if(dumpfile==NULL)
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{
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fprintf(stderr,"\nError opening output file\n");
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return -1;
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}
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printf("\nlistening on %s... Press Ctrl+C to stop...\n", d->description);
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/* At this point, we no longer need the device list. Free it */
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pcap_freealldevs(alldevs);
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/* start the capture */
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pcap_loop(adhandle, 0, packet_handler, (unsigned char *)dumpfile);
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return 0;
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}
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/* Callback function invoked by libpcap for every incoming packet */
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void packet_handler(u_char *dumpfile, const struct pcap_pkthdr *header, const u_char *pkt_data)
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{
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/* save the packet on the dump file */
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pcap_dump(dumpfile, header, pkt_data);
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}
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