hdw-sniff.c

   1 /*
   2  * hdw-sniff, sniffer using pcap lib
   3  *
   4  * author: hackbard@hackdaworld.dyndns.org
   5  */
   6
   7 #define _GNU_SOURCE
   8
   9 #include <stdio.h>
  10 #include <string.h>
  11 #include <stdlib.h>
  12 #include <sys/socket.h>
  13 #include <time.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16 #include <pcap.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <fcntl.h>
  20 #include <unistd.h>
  21 #include <sys/ioctl.h>
  22
  23 /* IEEE 802.3 stuff -- i will concentrate on .11 stuff before! */
  24 #include <netinet/if_ether.h>  /* for ethhdr struct */
  25 #include <netinet/ip.h> /* ip */
  26 #include <netinet/in.h> /* in_addr , inet_ntoa */
  27 #include <netinet/tcp.h> /* tcp header and protocols */
  28
  29 /* IEEE 802.11 stuff -- will become one include later ... */
  30 #include "ieee80211.h" /* from hunz's aeolus, short hostap_wlan.h */
  31 #include "ieee802_11.h" /* from pcmcia-cs */
  32
  33 #include "hdw-sniff.h" /* my functions */
  34
  35 /* global variables */
  36 int file_fd=0;
  37
  38 int main(int argc, char *argv[]) {
  39
  40         char pcap_error[PCAP_ERRBUF_SIZE];
  41         pcap_t *pcap_handle;
  42         int pcap_fd,foo_fd;
  43         fd_set pcap_fd_set;
  44         struct timeval fd_set_tv;
  45         char sys_call[30];
  46         struct info_struct my_info_struct;
  47
  48         /* parse the arguments */
  49         if(argc<3) {
  50                 printf("usage: %s <interface> <monitor mode> <logfile>\n",
  51                         argv[0]);
  52                 return 0;
  53         }
  54         if(argc!=4) {
  55                 printf("no logfile specified, writing to stdout ...\n");
  56         }
  57         else {
  58                 if((file_fd=open(argv[3],O_RDWR | O_CREAT))!=0) {
  59                         printf("writing to logfile %s ...\n",argv[3]);
  60                         dprintf(file_fd,"|iv - --|id|crypted_snap - --|\n");
  61                 }
  62                 else {
  63                         printf("can't open logfile. not logged to file!\n");
  64                 }
  65         }
  66
  67         /* setting up device and set monitor mode */
  68         if(atoi(argv[2])==1) {
  69                 printf("setting to monitor mode\n");
  70                 if(strncmp(argv[1],"wlan",4)==0)
  71                         sprintf(sys_call,"iwpriv %s monitor 3",argv[1]);
  72                 if(strncmp(argv[1],"eth",3)==0)
  73                         sprintf(sys_call,"ifconfig %s promisc",argv[1]);
  74         system(sys_call);
  75         }
  76         printf("setting up interface\n");
  77         sprintf(sys_call,"ifconfig %s up",argv[1]);
  78         system(sys_call);
  79
  80         /* start pcap session */
  81         pcap_handle=pcap_open_live(argv[1],BUFSIZ,1,-1,pcap_error);
  82         if(pcap_handle==NULL) {
  83                 printf("%s: %s\n",argv[0],pcap_error);
  84                 return 1;
  85         }
  86
  87         /* set non blocking */
  88         if((pcap_setnonblock(pcap_handle,1,pcap_error))==-1) {
  89                 printf("%s: %s\n",argv[0],pcap_error);
  90                 return 1;
  91         }
  92
  93         /* set info struct */
  94         my_info_struct.count=0;
  95         my_info_struct.mmode=argv[2][0];
  96         my_info_struct.ssid_list=(struct list *)malloc(sizeof(struct list));
  97         my_info_struct.ssid_list->next=NULL;
  98         // strcpy(my_info_struct.ssid_list->ssid,"test");
  99         strcpy(my_info_struct.dev,argv[1]);
 100
 101         /* prepare for select */
 102         pcap_fd=pcap_fileno(pcap_handle);
 103
 104         /* create file descriptor */
 105         if((foo_fd=socket(AF_INET,SOCK_DGRAM,0))==-1) {
 106                 printf("unable to create socket foo_fd\n");
 107                 return -1;
 108         }
 109
 110         /* do loopp */
 111         while (1) {
 112
 113                 /* set pcap_fd */
 114                 FD_ZERO(&pcap_fd_set);
 115                 FD_SET(pcap_fd,&pcap_fd_set);
 116                 fd_set_tv.tv_sec=0;
 117                 fd_set_tv.tv_usec=200000;
 118
 119                 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);
 120                 else if((hop_channel(&my_info_struct,foo_fd))==-1) {
 121                         printf("channelhopping failed, aborting\n");
 122                         return -1;
 123                 }
 124         }
 125         return 0;
 126 }
 127
 128
 129 /* pcap_process callback function */
 130 void pcap_process(u_char *info,const struct pcap_pkthdr *pcap_header,
 131                         const u_char *package) {
 132
 133         /* local variables */
 134         char tmp_buf[20],tmp_buf1[10],tmp_buf2[32];
 135         unsigned char crypted_snap[12];
 136         struct linux_wlan_ng_prism_hdr *prism_hdr;
 137         struct ieee802_11_hdr *w_hdr;
 138         struct snaphdr *snap_hdr;
 139         struct beacon_struct *beacon_hdr;
 140         struct ethhdr *e_hdr;
 141         struct info_struct *my_info_struct;
 142         int i,p_o,w_o,e_o,i_o,special_o=0;
 143
 144         my_info_struct=(struct info_struct *)info;
 145         ++(my_info_struct->count);
 146
 147         /* cache offsets */
 148         p_o=((strncmp(my_info_struct->dev,"wlan",4)==0)?sizeof(struct linux_wlan_ng_prism_hdr):0);
 149         w_o=((strncmp(my_info_struct->dev,"wlan",4)==0)?sizeof(struct ieee802_11_hdr):0);
 150         e_o=sizeof(struct ethhdr);
 151         i_o=sizeof(struct iphdr);
 152
 153         /* new package */
 154         printf("\n");
 155         printf("---> package %d ---- %s",my_info_struct->count,
 156                         ctime((const time_t*)&(pcap_header->ts.tv_sec)));
 157
 158         /* pcap header */
 159         printf("pcap header: ");
 160         printf("capture_length(dec): %d\t",pcap_header->caplen);
 161         printf("off_wire_length(dec): %d\n",pcap_header->len);
 162
 163         /* wireless stuff */
 164         /* prism wlan ng headers */
 165         if((my_info_struct->mmode-0x30==1) &
 166                 (strncmp(my_info_struct->dev,"wlan",4)==0)) {
 167         printf("prism header: (%d bytes)\n",p_o);
 168         prism_hdr=(struct linux_wlan_ng_prism_hdr *)package;
 169         printf("| message code/length: %d/%d |\t",prism_hdr->msgcode,
 170                                                 prism_hdr->msglen);
 171         printf("device: %s |\n",prism_hdr->devname);
 172         /* ieee802.11 header */
 173
 174         /* we need smaller w_hdr for non distributed frames */
 175         if((w_hdr->frame_ctl & (1<<8)) & (w_hdr->frame_ctl & (1<<9))) {
 176                 printf("=> distributed packet !!!!11\n");
 177         } else w_o-=(sizeof(struct snaphdr)-sizeof(unsigned short));
 178
 179         printf("ieee802.11 header: (%d bytes)\n",w_o);
 180         w_hdr=(struct ieee802_11_hdr *)(package+p_o);
 181
 182         printf("fc: ");
 183         for(i=0;i<16;i++)
 184                 printf("%s%d%s",(i==0?"|":""),
 185                                 (((w_hdr->frame_ctl) & (1<<i))>0?1:0),
 186                                 (i==15?"|\n":"|"));
 187         printf("    | v | t |  s-t  |t|f|m|r|p|m|w|o|\n");
 188         /* frame type */
 189         /* management */
 190         if(!(w_hdr->frame_ctl & 0x0c)) {
 191         tmp_buf1[0]='\0'; tmp_buf2[0]='\0';
 192         if((w_hdr->frame_ctl & IEEE802_11_STYPE_ASSOC_REQ)>0)
 193                 strcpy(tmp_buf,"association request");
 194         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_ASSOC_RESP)>0)
 195                 strcpy(tmp_buf,"association response");
 196         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_REASSOC_REQ)>0)
 197                 strcpy(tmp_buf,"reassociation request");
 198         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_REASSOC_RESP)>0)
 199                 strcpy(tmp_buf,"reassociation response");
 200         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_PROBE_REQ)>0)
 201                 strcpy(tmp_buf,"probe request");
 202         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_PROBE_RESP)>0)
 203                 strcpy(tmp_buf,"probe response");
 204         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_BEACON)==IEEE802_11_STYPE_BEACON) {
 205                 beacon_hdr=(struct beacon_struct *)(package+p_o+w_o);
 206                 beacon_hdr->ssid_s.elementid==0?strcpy(tmp_buf1,"essid = ")
 207                                                 :strcpy(tmp_buf1,"ibssid = ");
 208                 strncpy(tmp_buf2,beacon_hdr->ssid_s.ssid,
 209                                 beacon_hdr->ssid_s.length);
 210                 tmp_buf2[beacon_hdr->ssid_s.length]='\0';
 211                 strcpy(tmp_buf,"beacon");
 212                 add_ssid_2_list(tmp_buf2,my_info_struct->ssid_list);
 213         }
 214         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_ATIM)>0)
 215                 strcpy(tmp_buf,"announcement traffic indication message");
 216         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_DISASSOC)>0)
 217                 strcpy(tmp_buf,"disassociation");
 218         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_AUTH)>0)
 219                 strcpy(tmp_buf,"authentification");
 220         else if((w_hdr->frame_ctl & IEEE802_11_STYPE_DEAUTH)>0)
 221                 strcpy(tmp_buf,"deauthentification");
 222         else strcpy(tmp_buf,"impossible situation \%) - go mail the author.");
 223         }
 224         else strcpy(tmp_buf,"control or data frame type");
 225
 226         printf("=> %s\n",tmp_buf);
 227         if(strlen(tmp_buf1)>0 & strlen(tmp_buf2)>0) printf("   %s%s\n",
 228                                                         tmp_buf1,
 229                                                         tmp_buf2);
 230         printf("duration/id: 0x%x\n",w_hdr->duration_id);
 231         printf("version check ... %s\n",
 232         ((w_hdr->frame_ctl & IEEE802_11_FCTL_VERS)==0x00)?
 233                                                         "ok":"unknown");
 234         }
 235
 236         /* ethernet */
 237         if((strncmp(my_info_struct->dev,"eth",3)==0) |
 238         ((w_hdr->frame_ctl & IEEE802_11_FTYPE_DATA)==IEEE802_11_FTYPE_DATA)) {
 239
 240         if((strncmp(my_info_struct->dev,"eth",3)==0)) {
 241                 printf("ethernet: (%d bytes)\n",e_o);
 242                 e_hdr=(struct ethhdr *)(package+p_o+w_o);
 243                 special_o=sizeof(struct ethhdr);
 244                 /* what types ? */
 245                 printf("type = ");
 246                 printf("%x  ",ntohs(e_hdr->h_proto));
 247                 printf("dest_addr = ");
 248                 for(i=0;i<ETH_ALEN;i++)
 249                 printf("%x%s",*(e_hdr->h_dest+i),((i==ETH_ALEN-1)?" ":":"));
 250                 printf(" src_addr = ");
 251                 for(i=0;i<ETH_ALEN;i++) printf("%x%s",*(e_hdr->h_source+i),
 252                                                 ((i==ETH_ALEN-1)?"\n":":"));
 253                 if((ntohs(e_hdr->h_proto)==ETH_P_IP))
 254                                         parse_ip(package+p_o+w_o+e_o);
 255         }
 256         else {
 257                 snap_hdr=(struct snaphdr *)(package+p_o+w_o);
 258                 if((snap_hdr->snap[0]==0xaa) &
 259                    (snap_hdr->snap[1]==0xaa) &
 260                    (snap_hdr->snap[2]==0x03) &
 261                    (snap_hdr->snap[3]==0x00) &
 262                    (snap_hdr->snap[4]==0x00) &
 263                    (snap_hdr->snap[5]==0x00)) {
 264                         printf("- no encryption!\n");
 265                         if(snap_hdr->proto==ntohs(ETH_P_IP)) {
 266                                 e_o=sizeof(struct snaphdr);
 267                                 parse_ip(snap_hdr+e_o);
 268                         }
 269
 270                 }
 271                 else {
 272                         printf("- crypted packet!\n");
 273                         /* print crypted snap - write into file */
 274                         printf("snap: (iv(3) + index(1) + crypted snap(6)) ");
 275                         for(i=0;i<10;i++) {
 276                                 printf("%x ",*(snap_hdr->snap+i));
 277                                 crypted_snap[i]=*(snap_hdr->snap+i);
 278                         }
 279                         /* xor with plain
 280                         crypted_snap[4]^=0xaa;
 281                         crypted_snap[5]^=0xaa;
 282                         crypted_snap[6]^=0x03;
 283                         crypted_snap[7]^=0x00;
 284                         crypted_snap[8]^=0x00;
 285                         crypted_snap[9]^=0x00;
 286                         */
 287
 288                         printf("\n");
 289                         crypted_snap[10]='\0';
 290                         crypted_snap[11]='\n';
 291
 292                         if(file_fd>0) {
 293                                 printf("debug: saved to file\n");
 294                                 dprintf(file_fd,IVLINE,IVL_ARGS);
 295                         }
 296                 }
 297         }
 298         }
 299
 300         /* dump it */
 301 #ifdef SHOW_HEX
 302         printf("all dump: (hex)\n");
 303         for(i=p_o+w_o+special_o;i<pcap_header->caplen;i++)
 304                 printf("%x ",*(package+i));
 305         printf("\n");
 306 #endif
 307 #ifdef DEBUG_CHAR
 308         printf("all dump: (char)\n");
 309         for(i=p_o+w_o;i<pcap_header->caplen;i++)
 310                 printf("%c ",*(package+i));
 311         printf("\n");
 312 #endif
 313 }
 314
 315 int hop_channel(struct info_struct *info,int foo_fd) {
 316         if((info->mmode-0x30==1) && (strncmp(info->dev,"wlan",4)==0)) {
 317
 318         struct iwreq my_iwreq;
 319
 320         if (info->channel>=C_MAX) info->channel=1;
 321
 322         memset(&my_iwreq,0,sizeof(my_iwreq));
 323         strcpy(my_iwreq.ifr_name,info->dev);
 324         my_iwreq.u.freq.e=0;
 325         my_iwreq.u.freq.m=info->channel;
 326         if((ioctl(foo_fd,SIOCSIWFREQ,&my_iwreq))==-1) {
 327                 printf("unable to hop channels\n");
 328                 perror("ioctl");
 329                 return -1;
 330         }
 331         ++(info->channel);
 332         }
 333         return 0;
 334 }
 335
 336 int parse_ip(char *ip_o) {
 337         struct iphdr *ip_hdr;
 338         int i;
 339
 340         printf("ip protocol:\n");
 341         ip_hdr=(struct iphdr *)ip_o;
 342         printf("version = %x ",ip_hdr->version);
 343         printf("header_length = %x \n",ip_hdr->ihl);
 344         printf("service = %x ",ip_hdr->tos);
 345         printf("total_length(dec.) = %d \n",ip_hdr->tot_len);
 346         printf("source_ip: ");
 347                 for(i=0;i<=3;++i) {
 348                         printf("%d%s",
 349                         (ip_hdr->saddr&(0xff<<(8*i)))>>(8*i),
 350                         (i==3?"\n":"."));
 351                 }
 352         printf("destination_ip: ");
 353         for(i=0;i<=3;++i) {
 354                 printf("%d%s",
 355                 (ip_hdr->daddr&(0xff<<(8*i)))>>(8*i),
 356                 (i==3?"\n":"."));
 357         }
 358         printf("ip_id = %x ",ntohs(ip_hdr->id));
 359         printf("ip_offset = %x \n",ip_hdr->frag_off);
 360         printf("time2live = %x ip_proto = %x\n",ip_hdr->ttl,ip_hdr->protocol);
 361         /* how to continue */
 362         if(ip_hdr->protocol==IPPROTO_TCP)
 363                         parse_tcp(ip_hdr+sizeof(struct iphdr));
 364         if(ip_hdr->protocol==IPPROTO_UDP)
 365                         printf("udp package! get's parsed in the future\n");
 366         // printf("chksum: %x\n",ntohs(ip_hdr->ip_sum));
 367 }
 368
 369 int parse_tcp(char *tcp_o) {
 370         struct tcphdr *tcp_hdr;
 371
 372         printf("tcp protocol:\n");
 373         tcp_hdr=(struct tcphdr *)tcp_o;
 374         printf("source port: %d - dest port: %d\n",ntohs(tcp_hdr->source),
 375                                                 ntohs(tcp_hdr->dest));
 376         printf("sequence: %d - ack sequence: %d\n",ntohs(tcp_hdr->seq),
 377                                                 ntohs(tcp_hdr->ack_seq));
 378         printf("offset to data: %d - checksumm: %d\n",ntohs(tcp_hdr->doff)
 379                                                 ,ntohs(tcp_hdr->check));
 380         return 1;
 381 }