hdw-sniff.c

   1 /*
   2  * hdw-sniff, sniffer using pcap lib
   3  *
   4  * author: hackbard@hackdaworld.dyndns.org
   5  */
   6
   7 #include <stdio.h>
   8 #include <pcap.h>
   9
  10 /* IEEE 802.3 stuff -- i will concentrate on .11 stuff before! */
  11 #include <netinet/if_ether.h>
  12
  13 /* IEEE 802.11 stuff -- will become one include later ... */
  14 #include "ieee80211.h" /* from hunz's aeolus, short hostap_wlan.h */
  15 #include "ieee802_11.h" /* from pcmcia-cs */
  16
  17 #include "hdw-sniff.h" /* my functions */
  18
  19 #define MAX_PACKAGES 3
  20
  21 int main(int argc, char *argv[]) {
  22
  23         int i,count;
  24         char pcap_error[PCAP_ERRBUF_SIZE];
  25         pcap_t *pcap_handle;
  26         const u_char *package;
  27         struct pcap_pkthdr pcap_header;
  28         struct ethhdr *e_hdr;
  29         struct ip *ip_hdr;
  30         struct ieee802_11_hdr *w_hdr;
  31
  32         /* parse the arguments */
  33         if(argc<2) {
  34                 printf("usage: %s <interface> <logfile>\n",argv[0]);
  35                 return 0;
  36         }
  37         if(argc!=3) {
  38                 printf("no logfile specified, writing to stdout ...\n");
  39         }
  40
  41         /* start pcap session */
  42         pcap_handle=pcap_open_live(argv[1],BUFSIZ,1,-1,pcap_error);
  43         if(pcap_handle==NULL) {
  44                 printf("%s: %s\n",argv[0],pcap_error);
  45                 return 1;
  46         }
  47
  48         /* grab a package until user breaks */
  49         count=0;
  50         while (count<MAX_PACKAGES) {
  51         count++;
  52         printf("\n");
  53         if((package=pcap_next(pcap_handle,&pcap_header))!=NULL) {
  54                 printf("---> package %d ---- %s",count,
  55                                 ctime((const time_t*)&pcap_header.ts.tv_sec));
  56                 printf("pcap header: ");
  57                 printf("capture length=%d ",pcap_header.caplen);
  58                 printf("length(off wire)=%d\n",pcap_header.len);
  59         }
  60
  61         /* is ieee802.11 ? -- we assume yes :) */
  62
  63
  64         /* ethernet */
  65         e_hdr=(struct ethhdr *)package;
  66         /* what types ? */
  67         printf("types = ");
  68         printf("%x  ",ntohs(e_hdr->h_proto));
  69         printf("dest_addr = ");
  70         for(i=0;i<ETH_ALEN;i++)
  71         printf("%x%s",*(e_hdr->h_dest+i),((i==ETH_ALEN-1)?" ":":"));
  72         printf(" src_addr = ");
  73         for(i=0;i<ETH_ALEN;i++)
  74         printf("%x%s",*(e_hdr->h_source+i),((i==ETH_ALEN-1)?"\n":":"));
  75         if(ntohs(e_hdr->h_proto)==ETH_P_IP) {
  76                 printf("ip protocol: ");
  77                 ip_hdr=(struct ip *)(package+sizeof(struct ethhdr));
  78                 printf("version = %x ",ntohs(ip_hdr->ip_v:4));
  79                 printf("header length = %x\n",ntohs(ip_hdr->ip_hl:4));
  80         }
  81         printf("rest:\n");
  82         for(i=sizeof(struct ethhdr);i<pcap_header.caplen;i++)
  83                 printf("%x ",*(package+i));
  84         printf("\n");
  85         }
  86         printf("\n");
  87         printf("just beacon frames, ha? - wake up early! :)\n");
  88         printf("\n");
  89 }