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>  /* for ethhdr struct */
  12 #include <netinet/ip.h> /* ip */
  13 #include <netinet/in.h> /* in_addr */
  14
  15 /* IEEE 802.11 stuff -- will become one include later ... */
  16 #include "ieee80211.h" /* from hunz's aeolus, short hostap_wlan.h */
  17 #include "ieee802_11.h" /* from pcmcia-cs */
  18
  19 #include "hdw-sniff.h" /* my functions */
  20
  21 int main(int argc, char *argv[]) {
  22
  23         char pcap_error[PCAP_ERRBUF_SIZE];
  24         pcap_t *pcap_handle;
  25         char sys_call[30];
  26         FILE *logfile;
  27         int count;
  28         int *p_count;
  29
  30         /* parse the arguments */
  31         if(argc<3) {
  32                 printf("usage: %s <interface> <monitor mode> <logfile>\n",argv[0]);
  33                 return 0;
  34         }
  35         if(argc!=4) {
  36                 printf("no logfile specified, writing to stdout ...\n");
  37         }
  38         else {
  39                 if((logfile=fopen(argv[3],"w"))!=NULL) {
  40                         printf("writing to logfile %s ...\n",argv[3]);
  41                 }
  42                 else {
  43                         printf("can't open logfile!\n");
  44                 }
  45         }
  46
  47         /* setting up device and set monitor mode */
  48         if(atoi(argv[2])==1 && (strncmp(argv[1],"wlan",4)==0)) {
  49                 printf("setting to monitor mode 3\n");
  50                 sprintf(sys_call,"iwpriv %s monitor 3",argv[1]);
  51                 system(sys_call);
  52         }
  53         printf("setting up interface\n");
  54         sprintf(sys_call,"ifconfig %s up",argv[1]);
  55         system(sys_call);
  56
  57         /* start pcap session */
  58         pcap_handle=pcap_open_live(argv[1],BUFSIZ,1,-1,pcap_error);
  59         if(pcap_handle==NULL) {
  60                 printf("%s: %s\n",argv[0],pcap_error);
  61                 return 1;
  62         }
  63
  64         /* grab a package until user breaks */
  65         count=0;
  66         p_count=&count;
  67         pcap_dispatch(pcap_handle,-1,(pcap_handler)pcap_process,
  68                         (u_char *)&p_count);
  69 }
  70
  71
  72 /* pcap_process callback function */
  73 void pcap_process(u_char *count,const struct pcap_pkthdr *pcap_header,
  74                         const u_char *package) {
  75
  76         /* local variables */
  77         struct ethhdr *e_hdr;
  78         struct ip *ip_hdr;
  79         struct ieee802_11_hdr *w_hdr;
  80         int i;
  81         int *p_count;
  82
  83         p_count=(int *)count;
  84         ++(*p_count);
  85
  86         printf("\n");
  87         printf("---> package %d ---- %s",count,
  88                         ctime((const time_t*)pcap_header->ts.tv_sec));
  89         printf("pcap header: ");
  90         printf("capture length=%d ",pcap_header->caplen);
  91         printf("length(off wire)=%d\n",pcap_header->len);
  92
  93         /* is ieee802.11 ? -- we assume yes :) */
  94         /* ...                                  */
  95
  96
  97         /* ieee802.3 */
  98         /* ethernet */
  99         e_hdr=(struct ethhdr *)package;
 100         /* what types ? */
 101         printf("type = ");
 102         printf("%x  ",ntohs(e_hdr->h_proto));
 103         printf("dest_addr = ");
 104         for(i=0;i<ETH_ALEN;i++)
 105         printf("%x%s",*(e_hdr->h_dest+i),((i==ETH_ALEN-1)?" ":":"));
 106         printf(" src_addr = ");
 107         for(i=0;i<ETH_ALEN;i++)
 108         printf("%x%s",*(e_hdr->h_source+i),((i==ETH_ALEN-1)?"\n":":"));
 109                 /* IP ? */
 110         if(ntohs(e_hdr->h_proto)==ETH_P_IP) {
 111                 printf("ip protocol: ");
 112                 ip_hdr=(struct ip *)(package+sizeof(struct ethhdr));
 113                 printf("version = %x ",ntohs(ip_hdr->ip_v));
 114                 printf("header_length = %x \n",ntohs(ip_hdr->ip_hl));
 115                 printf("service = %x ",ntohs(ip_hdr->ip_tos));
 116                 printf("total_length(dec.) = %d \n",ntohs(ip_hdr->ip_len));
 117                 printf("ip_addresses: source = ");
 118                 printf("%s\tdestination = %s\n",inet_ntoa(ip_hdr->ip_src),
 119                                                 inet_ntoa(ip_hdr->ip_dst));
 120                 printf("ip_id = %x ",ntohs(ip_hdr->ip_id));
 121                 printf("ip_offset = %x \n",ntohs(ip_hdr->ip_off));
 122                 printf("time2live = %x ip_proto = %x\n",ntohs(ip_hdr->ip_ttl),
 123                                                 ntohs(ip_hdr->ip_p));
 124                 printf("chksum: %x\n",ntohs(ip_hdr->ip_sum));
 125
 126
 127         }
 128         printf("all_hex_dump:\n");
 129         for(i=sizeof(struct ethhdr);i<pcap_header->caplen;i++)
 130                 printf("%x ",*(package+i));
 131 }
 132
 133