winpcap/Examples-pcap/savedump/savedump.c

   1 #include "pcap.h"
   2
   3 /* prototype of the packet handler */
   4 void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data);
   5
   6 main(int argc, char **argv)
   7 {
   8         pcap_if_t *alldevs;
   9         pcap_if_t *d;
  10         int inum;
  11         int i=0;
  12         pcap_t *adhandle;
  13         char errbuf[PCAP_ERRBUF_SIZE];
  14         pcap_dumper_t *dumpfile;
  15
  16
  17     /* Check command line */
  18         if(argc != 2)
  19         {
  20         printf("usage: %s filename", argv[0]);
  21         return -1;
  22     }
  23
  24         /* Retrieve the device list on the local machine */
  25         if (pcap_findalldevs(&alldevs, errbuf) == -1)
  26         {
  27                 fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
  28                 exit(1);
  29         }
  30
  31     /* Print the list */
  32     for(d=alldevs; d; d=d->next)
  33     {
  34         printf("%d. %s", ++i, d->name);
  35         if (d->description)
  36             printf(" (%s)\n", d->description);
  37         else
  38             printf(" (No description available)\n");
  39     }
  40
  41     if(i==0)
  42     {
  43         printf("\nNo interfaces found! Make sure WinPcap is installed.\n");
  44         return -1;
  45     }
  46
  47     printf("Enter the interface number (1-%d):",i);
  48     scanf("%d", &inum);
  49
  50     if(inum < 1 || inum > i)
  51     {
  52         printf("\nInterface number out of range.\n");
  53         /* Free the device list */
  54         pcap_freealldevs(alldevs);
  55         return -1;
  56     }
  57
  58         /* Jump to the selected adapter */
  59     for(d=alldevs, i=0; i< inum-1 ;d=d->next, i++);
  60
  61
  62         /* Open the adapter */
  63         if ((adhandle= pcap_open_live(d->name,  // name of the device
  64                                                          65536,                 // portion of the packet to capture.
  65                                                                                         // 65536 grants that the whole packet will be captured on all the MACs.
  66                                                          1,                             // promiscuous mode (nonzero means promiscuous)
  67                                                          1000,                  // read timeout
  68                                                          errbuf                 // error buffer
  69                                                          )) == NULL)
  70         {
  71                 fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n", d->name);
  72                 /* Free the device list */
  73                 pcap_freealldevs(alldevs);
  74                 return -1;
  75         }
  76
  77         /* Open the dump file */
  78         dumpfile = pcap_dump_open(adhandle, argv[1]);
  79
  80         if(dumpfile==NULL)
  81         {
  82                 fprintf(stderr,"\nError opening output file\n");
  83                 return -1;
  84         }
  85
  86     printf("\nlistening on %s... Press Ctrl+C to stop...\n", d->description);
  87
  88     /* At this point, we no longer need the device list. Free it */
  89     pcap_freealldevs(alldevs);
  90
  91     /* start the capture */
  92     pcap_loop(adhandle, 0, packet_handler, (unsigned char *)dumpfile);
  93
  94     pcap_close(adhandle);
  95     return 0;
  96 }
  97
  98 /* Callback function invoked by libpcap for every incoming packet */
  99 void packet_handler(u_char *dumpfile, const struct pcap_pkthdr *header, const u_char *pkt_data)
 100 {
 101         /* save the packet on the dump file */
 102         pcap_dump(dumpfile, header, pkt_data);
 103 }