winpcap/Examples-pcap/readfile_ex/readfile_ex.c

   1 #include <stdio.h>
   2 #include <pcap.h>
   3
   4 #define LINE_LEN 16
   5
   6 int main(int argc, char **argv)
   7 {
   8         pcap_t *fp;
   9         char errbuf[PCAP_ERRBUF_SIZE];
  10         struct pcap_pkthdr *header;
  11         const u_char *pkt_data;
  12         u_int i=0;
  13         int res;
  14
  15         if(argc != 2)
  16         {
  17                 printf("usage: %s filename", argv[0]);
  18                 return -1;
  19
  20         }
  21
  22         /* Open the capture file */
  23         if ((fp = pcap_open_offline(argv[1],                    // name of the device
  24                                                  errbuf                                 // error buffer
  25                                                  )) == NULL)
  26         {
  27                 fprintf(stderr,"\nUnable to open the file %s.\n", argv[1]);
  28                 return -1;
  29         }
  30
  31         /* Retrieve the packets from the file */
  32         while((res = pcap_next_ex(fp, &header, &pkt_data)) >= 0)
  33         {
  34                 /* print pkt timestamp and pkt len */
  35                 printf("%ld:%ld (%ld)\n", header->ts.tv_sec, header->ts.tv_usec, header->len);
  36
  37                 /* Print the packet */
  38                 for (i=1; (i < header->caplen + 1 ) ; i++)
  39                 {
  40                         printf("%.2x ", pkt_data[i-1]);
  41                         if ( (i % LINE_LEN) == 0) printf("\n");
  42                 }
  43
  44                 printf("\n\n");
  45         }
  46
  47
  48         if (res == -1)
  49         {
  50                 printf("Error reading the packets: %s\n", pcap_geterr(fp));
  51         }
  52
  53         pcap_close(fp);
  54         return 0;
  55 }
  56