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 #include <sys/types.h>
  16 #include <unistd.h>
  17 #include <sys/ioctl.h>
  18
  19 /* IEEE 802.3 stuff -- i will concentrate on .11 stuff before! */
  20 #include <netinet/if_ether.h>  /* for ethhdr struct */
  21 #include <netinet/ip.h> /* ip */
  22 #include <netinet/in.h> /* in_addr , inet_ntoa */
  23
  24 /* IEEE 802.11 stuff -- will become one include later ... */
  25 #include "ieee80211.h" /* from hunz's aeolus, short hostap_wlan.h */
  26 #include "ieee802_11.h" /* from pcmcia-cs */
  27
  28 #include "hdw-sniff.h" /* my functions */
  29
  30 int main(int argc, char *argv[]) {
  31
  32         char pcap_error[PCAP_ERRBUF_SIZE];
  33         pcap_t *pcap_handle;
  34         int pcap_fd,foo_fd;
  35         fd_set pcap_fd_set;
  36         struct timeval fd_set_tv;
  37         char sys_call[30];
  38         FILE *logfile;
  39         struct info_struct my_info_struct;
  40
  41         /* parse the arguments */
  42         if(argc<3) {
  43                 printf("usage: %s <interface> <monitor mode> <logfile>\n",
  44                         argv[0]);
  45                 return 0;
  46         }
  47         if(argc!=4) {
  48                 printf("no logfile specified, writing to stdout ...\n");
  49         }
  50         else {
  51                 if((logfile=fopen(argv[3],"w"))!=NULL) {
  52                         printf("writing to logfile %s ...\n",argv[3]);
  53                 }
  54                 else {
  55                         printf("can't open logfile!\n");
  56                 }
  57         }
  58
  59         /* setting up device and set monitor mode */
  60         if(atoi(argv[2])==1) {
  61                 printf("setting to monitor mode\n");
  62                 if(strncmp(argv[1],"wlan",4)==0)
  63                         sprintf(sys_call,"iwpriv %s monitor 3",argv[1]);
  64                 if(strncmp(argv[1],"eth",3)==0)
  65                         sprintf(sys_call,"ifconfig %s promisc",argv[1]);
  66         system(sys_call);
  67         }
  68         printf("setting up interface\n");
  69         sprintf(sys_call,"ifconfig %s up",argv[1]);
  70         system(sys_call);
  71
  72         /* start pcap session */
  73         pcap_handle=pcap_open_live(argv[1],BUFSIZ,1,-1,pcap_error);
  74         if(pcap_handle==NULL) {
  75                 printf("%s: %s\n",argv[0],pcap_error);
  76                 return 1;
  77         }
  78
  79         /* set non blocking */
  80         if((pcap_setnonblock(pcap_handle,1,pcap_error))==-1) {
  81                 printf("%s: %s\n",argv[0],pcap_error);
  82                 return 1;
  83         }
  84
  85         /* grab a package until user breaks */
  86         my_info_struct.count=0;
  87         my_info_struct.mmode=argv[2][0];
  88         strcpy(my_info_struct.dev,argv[1]);
  89
  90         /* prepare for select */
  91         pcap_fd=pcap_fileno(pcap_handle);
  92
  93         /* create file descriptor */
  94         if((foo_fd=socket(AF_INET,SOCK_DGRAM,0))==-1) {
  95                 printf("unable to create socket foo_fd\n");
  96                 return -1;
  97         }
  98
  99         /* do loopp */
 100         while (1) {
 101
 102                 /* set pcap_fd */
 103                 FD_ZERO(&pcap_fd_set);
 104                 FD_SET(pcap_fd,&pcap_fd_set);
 105                 fd_set_tv.tv_sec=0;
 106                 fd_set_tv.tv_usec=200000;
 107
 108                 if((select(pcap_fd+1,&pcap_fd_set,NULL,NULL,&fd_set_tv)) && (FD_ISSET(pcap_fd,&pcap_fd_set))) pcap_dispatch(pcap_handle,-1,pcap_process,(u_char *)&my_info_struct);
 109                 else if((hop_channel(&my_info_struct,foo_fd))==-1) {
 110                         printf("channelhopping failed, aborting\n");
 111                         return -1;
 112                 }
 113         }
 114         return 0;
 115 }
 116
 117
 118 /* pcap_process callback function */
 119 void pcap_process(u_char *info,const struct pcap_pkthdr *pcap_header,
 120                         const u_char *package) {
 121
 122         /* local variables */
 123         struct linux_wlan_ng_prism_hdr *prism_hdr;
 124         struct ieee802_11_hdr *w_hdr;
 125         struct ethhdr *e_hdr;
 126         struct iphdr *ip_hdr;
 127         struct info_struct *my_info_struct;
 128         int i,p_o,w_o,e_o,i_o;
 129
 130         my_info_struct=(struct info_struct *)info;
 131         ++(my_info_struct->count);
 132
 133         /* cache offsets */
 134         p_o=((strncmp(my_info_struct->dev,"wlan",4)==0)?sizeof(struct linux_wlan_ng_prism_hdr):0);
 135         w_o=((strncmp(my_info_struct->dev,"wlan",4)==0)?sizeof(struct ieee802_11_hdr):0);
 136         e_o=sizeof(struct ethhdr);
 137         i_o=sizeof(struct iphdr);
 138
 139         printf("\n");
 140         printf("---> package %d ---- %s",my_info_struct->count,
 141                         ctime((const time_t*)&(pcap_header->ts.tv_sec)));
 142         printf("pcap header:\n");
 143         printf("capture_length: %d (dec.)\t",pcap_header->caplen);
 144         printf("length(off wire): %d (dec.)\n",pcap_header->len);
 145
 146         /* prism wlan ng headers */
 147         if((my_info_struct->mmode-0x30==1) &&
 148                 (strncmp(my_info_struct->dev,"wlan",4)==0)) {
 149         printf("prism header: (%d bytes)\n",p_o);
 150         prism_hdr=(struct linux_wlan_ng_prism_hdr *)package;
 151         printf("message code/length: %d/%d\n",ntohs(prism_hdr->msgcode),
 152                                                 ntohs(prism_hdr->msglen));
 153         printf("device: %s\n",prism_hdr->devname);
 154         /* skip wlan_ng_prism header */
 155         // package=package+p_o;
 156
 157         /* ieee802.11 header */
 158         printf("ieee802.11 header: (%d bytes)\n",w_o);
 159         w_hdr=(struct ieee802_11_hdr *)(package+p_o);
 160
 161         printf("debug:\n");
 162         for(i=0;i<16;i++) {
 163                 printf("%x -> ",1<<i);
 164                 printf("%x\n",(ntohs(w_hdr->frame_ctl) & (1<<i)));
 165         }
 166         printf("frame_control: %x duration_id: %x\n",ntohs(w_hdr->frame_ctl),
 167                                                 ntohs(w_hdr->duration_id));
 168         printf("version check ... %s\n",
 169         ((ntohs(w_hdr->frame_ctl) & IEEE802_11_FCTL_VERS)==0x00)?
 170                                                         "ok":"unknown");
 171         // printf("type:
 172         /* skip ieee802.11 header */
 173         // package=package+w_o;
 174         }
 175
 176         /* ieee802.3 */
 177         /* ethernet */
 178         printf("ethernet: (%d bytes)\n",e_o);
 179         e_hdr=(struct ethhdr *)(package+p_o+w_o);
 180         /* what types ? */
 181         printf("type = ");
 182         printf("%x  ",ntohs(e_hdr->h_proto));
 183         printf("dest_addr = ");
 184         for(i=0;i<ETH_ALEN;i++)
 185         printf("%x%s",*(e_hdr->h_dest+i),((i==ETH_ALEN-1)?" ":":"));
 186         printf(" src_addr = ");
 187         for(i=0;i<ETH_ALEN;i++)
 188         printf("%x%s",*(e_hdr->h_source+i),((i==ETH_ALEN-1)?"\n":":"));
 189
 190                 /* IP ? */
 191         if(ntohs(e_hdr->h_proto)==ETH_P_IP) {
 192                 printf("ip protocol: (%d bytes)\n",i_o);
 193                 ip_hdr=(struct iphdr *)(package+p_o+w_o+e_o);
 194                 printf("version = %x ",ntohs(ip_hdr->version));
 195                 printf("header_length = %x \n",ntohs(ip_hdr->ihl));
 196                 printf("service = %x ",ntohs(ip_hdr->tos));
 197                 printf("total_length(dec.) = %d \n",ntohs(ip_hdr->tot_len));
 198                 printf("source_ip: ");
 199                 for(i=3;i>=0;--i) {
 200                         printf("%d%s",
 201                         ip_hdr->saddr&0xff<<i,
 202                         (i==0?"\n":"."));
 203                 }
 204                 printf("destination_ip: ");
 205                 for(i=3;i>=0;--i) {
 206                         printf("%d%s",
 207                         ip_hdr->daddr&0xff<<i,
 208                         (i==0?"\n":"."));
 209                 }
 210                 // printf("ip_addresses: source = ");
 211                 // printf("%s\tdestination = %s\n",inet_ntoa(ip_hdr->saddr),
 212                 //                              inet_ntoa(ip_hdr->daddr));
 213                 printf("ip_id = %x ",ntohs(ip_hdr->id));
 214                 printf("ip_offset = %x \n",ntohs(ip_hdr->frag_off));
 215                 printf("time2live = %x ip_proto = %x\n",ntohs(ip_hdr->ttl),
 216                                                 ntohs(ip_hdr->protocol));
 217                 // printf("chksum: %x\n",ntohs(ip_hdr->ip_sum));
 218         }
 219         printf("all ethernet dump: (hex)\n");
 220         for(i=p_o+w_o+e_o;i<pcap_header->caplen;i++)
 221                 printf("%x ",*(package+i));
 222         printf("\n");
 223         printf("all ethernet dump: (char)\n");
 224         for(i=p_o+w_o+e_o;i<pcap_header->caplen;i++)
 225                 printf("%c ",*(package+i));
 226         printf("\n");
 227 }
 228
 229 int hop_channel(struct info_struct *info,int foo_fd) {
 230         if((info->mmode-0x30==1) && (strncmp(info->dev,"wlan",4)==0)) {
 231
 232         struct iwreq my_iwreq;
 233
 234         if (info->channel>=14) info->channel=1;
 235
 236         memset(&my_iwreq,0,sizeof(my_iwreq));
 237         strcpy(my_iwreq.ifr_name,info->dev);
 238         printf("debug: channel = %d\n",info->channel);
 239         my_iwreq.u.freq.e=0;
 240         my_iwreq.u.freq.m=info->channel;
 241         if((ioctl(foo_fd,SIOCSIWFREQ,&my_iwreq))==-1) {
 242                 printf("unable to hop channels\n");
 243                 perror("ioctl");
 244                 return -1;
 245         }
 246         ++(info->channel);
 247         }
 248         return 0;
 249 }