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 <string.h>
   9 #include <stdlib.h>
  10 #include <sys/socket.h>
  11 #include <time.h>
  12 #include <netinet/in.h>
  13 #include <arpa/inet.h>
  14 #include <pcap.h>
  15
  16 /* IEEE 802.3 stuff -- i will concentrate on .11 stuff before! */
  17 #include <netinet/if_ether.h>  /* for ethhdr struct */
  18 #include <netinet/ip.h> /* ip */
  19 #include <netinet/in.h> /* in_addr , inet_ntoa */
  20
  21 /* IEEE 802.11 stuff -- will become one include later ... */
  22 #include "ieee80211.h" /* from hunz's aeolus, short hostap_wlan.h */
  23 #include "ieee802_11.h" /* from pcmcia-cs */
  24
  25 #include "hdw-sniff.h" /* my functions */
  26
  27 int main(int argc, char *argv[]) {
  28
  29         char pcap_error[PCAP_ERRBUF_SIZE];
  30         pcap_t *pcap_handle;
  31         char sys_call[30];
  32         FILE *logfile;
  33         struct info_struct my_info_struct;
  34
  35         /* parse the arguments */
  36         if(argc<3) {
  37                 printf("usage: %s <interface> <monitor mode> <logfile>\n",
  38                         argv[0]);
  39                 return 0;
  40         }
  41         if(argc!=4) {
  42                 printf("no logfile specified, writing to stdout ...\n");
  43         }
  44         else {
  45                 if((logfile=fopen(argv[3],"w"))!=NULL) {
  46                         printf("writing to logfile %s ...\n",argv[3]);
  47                 }
  48                 else {
  49                         printf("can't open logfile!\n");
  50                 }
  51         }
  52
  53         /* setting up device and set monitor mode */
  54         if(atoi(argv[2])==1) {
  55                 printf("setting to monitor mode\n");
  56                 if(strncmp(argv[1],"wlan",4)==0)
  57                         sprintf(sys_call,"iwpriv %s monitor 3",argv[1]);
  58                 if(strncmp(argv[1],"eth",3)==0)
  59                         sprintf(sys_call,"ifconfig %s promisc",argv[1]);
  60         system(sys_call);
  61         }
  62         printf("setting up interface\n");
  63         sprintf(sys_call,"ifconfig %s up",argv[1]);
  64         system(sys_call);
  65
  66         /* start pcap session */
  67         pcap_handle=pcap_open_live(argv[1],BUFSIZ,1,-1,pcap_error);
  68         if(pcap_handle==NULL) {
  69                 printf("%s: %s\n",argv[0],pcap_error);
  70                 return 1;
  71         }
  72
  73         /* grab a package until user breaks */
  74         my_info_struct.count=0;
  75         my_info_struct.mmode=argv[2][0];
  76         strcpy(my_info_struct.dev,argv[1]);
  77         /* do loopp */
  78         pcap_loop(pcap_handle,-1,pcap_process,(u_char *)&my_info_struct);
  79         return 0;
  80 }
  81
  82
  83 /* pcap_process callback function */
  84 void pcap_process(u_char *info,const struct pcap_pkthdr *pcap_header,
  85                         const u_char *package) {
  86
  87         /* local variables */
  88         struct ethhdr *e_hdr;
  89         struct ip *ip_hdr;
  90         struct ieee802_11_hdr *w_hdr;
  91         struct info_struct *my_info_struct;
  92         int i;
  93
  94         my_info_struct=(struct info_struct *)info;
  95         ++(my_info_struct->count);
  96
  97         printf("\n");
  98         printf("---> package %d ---- %s",my_info_struct->count,
  99                         ctime((const time_t*)&(pcap_header->ts.tv_sec)));
 100         printf("pcap header: ");
 101         printf("capture length=%d ",pcap_header->caplen);
 102         printf("length(off wire)=%d\n",pcap_header->len);
 103
 104         /* is ieee802.11 ? -- we assume yes :) */
 105         if((my_info_struct->mmode-0x30==1) &&
 106                 (strncmp(my_info_struct->dev,"wlan",4)==0)) {
 107         printf("debug: ieee802.11\n");
 108         }
 109
 110
 111         /* ieee802.3 */
 112         /* ethernet */
 113         e_hdr=(struct ethhdr *)package;
 114         /* what types ? */
 115         printf("type = ");
 116         printf("%x  ",ntohs(e_hdr->h_proto));
 117         printf("dest_addr = ");
 118         for(i=0;i<ETH_ALEN;i++)
 119         printf("%x%s",*(e_hdr->h_dest+i),((i==ETH_ALEN-1)?" ":":"));
 120         printf(" src_addr = ");
 121         for(i=0;i<ETH_ALEN;i++)
 122         printf("%x%s",*(e_hdr->h_source+i),((i==ETH_ALEN-1)?"\n":":"));
 123                 /* IP ? */
 124         if(ntohs(e_hdr->h_proto)==ETH_P_IP) {
 125                 printf("ip protocol: ");
 126                 ip_hdr=(struct ip *)(package+sizeof(struct ethhdr));
 127                 printf("version = %x ",ntohs(ip_hdr->ip_v));
 128                 printf("header_length = %x \n",ntohs(ip_hdr->ip_hl));
 129                 printf("service = %x ",ntohs(ip_hdr->ip_tos));
 130                 printf("total_length(dec.) = %d \n",ntohs(ip_hdr->ip_len));
 131                 printf("ip_addresses: source = ");
 132                 printf("%s\tdestination = %s\n",inet_ntoa(ip_hdr->ip_src),
 133                                                 inet_ntoa(ip_hdr->ip_dst));
 134                 printf("ip_id = %x ",ntohs(ip_hdr->ip_id));
 135                 printf("ip_offset = %x \n",ntohs(ip_hdr->ip_off));
 136                 printf("time2live = %x ip_proto = %x\n",ntohs(ip_hdr->ip_ttl),
 137                                                 ntohs(ip_hdr->ip_p));
 138                 printf("chksum: %x\n",ntohs(ip_hdr->ip_sum));
 139         }
 140         printf("all_hex_dump:\n");
 141         for(i=sizeof(struct ethhdr);i<pcap_header->caplen;i++)
 142                 printf("%x ",*(package+i));
 143         printf("\n");
 144 }
 145
 146