/*
    This is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This software is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    For a copy of the GNU General Public License write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <signal.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/wireless.h>
#include <stdint.h>

#ifndef SIOCIWFIRSTPRIV
#define SIOCIWFIRSTPRIV SIOCDEVPRIVATE
#endif

/*===============================================================*/
/* Declarations */  //With thanks to the linux-wlan-ng project

#define WLAN_DEVNAMELEN_MAX 16

#define P80211ENUM_truth_false                  0
#define P80211ENUM_truth_true                   1
#define P80211ENUM_msgitem_status_no_value              1

/*===============================================================*/
/* Types */

/*----------------------------------------------------------------*/
/* A ptr to the following structure type is passed as the third */
/*  argument to the ioctl system call when issuing a request to */
/*  the p80211 module. */

/* message data item for INT, BOUNDEDINT, ENUMINT */
typedef struct p80211item_uint32
{
        uint32_t                did;
        uint16_t                status;
        uint16_t                len;
        uint32_t                data;
}  p80211item_uint32_t;

#define DIDmsg_lnxreq_wlansniff 0x0043
#define DIDmsg_lnxreq_wlansniff_enable 0x1043
#define DIDmsg_lnxreq_wlansniff_channel 0x2043
#define DIDmsg_lnxreq_wlansniff_resultcode 0x3043

typedef struct p80211msg_lnxreq_wlansniff
{
        uint32_t                msgcode;
        uint32_t                msglen;
        uint8_t             devname[WLAN_DEVNAMELEN_MAX];
        p80211item_uint32_t     enable;
        p80211item_uint32_t     channel;
        p80211item_uint32_t     resultcode;
}  p80211msg_lnxreq_wlansniff_t;

void usage(char *name) {
   fprintf(stderr, "usage: %s [-i devname] [-d | -e channel]\n", name);
   fprintf(stderr, "\t-i to specify your Orinoco device name (default eth0)\n");
   fprintf(stderr, "\t-d to disable monitor mode\n");
   fprintf(stderr, "\t-e to enable monitor mode and specify channel (default 6)\n");
   exit(1);
}

int main(int argc, char **argv)
{
   p80211msg_lnxreq_wlansniff_t sniff;
   char dev[WLAN_DEVNAMELEN_MAX + 1] = "eth0";
   int channel = 6;
   int enable = 0;

   int result = -1;
   int fd;
   
   struct iwreq ireq;  //for Orinoco

   while(1) {
      result = getopt(argc, argv, "i:e:d");
      if (result < 0) break;
      switch (result) {
      case 'i':
         strncpy(dev, optarg, WLAN_DEVNAMELEN_MAX);
         dev[WLAN_DEVNAMELEN_MAX] = 0;
         break;
      case 'd':
         enable = 0;
         break;
      case 'e':
         channel = atoi(optarg);
         enable = 1;
         break;
      default:
         usage(argv[0]);
      }
   }

   memset(&sniff, 0, sizeof(p80211msg_lnxreq_wlansniff_t));
   sniff.msgcode = DIDmsg_lnxreq_wlansniff;
   sniff.msglen = sizeof(p80211msg_lnxreq_wlansniff_t);
   strcpy((char*) sniff.devname, dev);

   sniff.enable.did = DIDmsg_lnxreq_wlansniff_enable;
   sniff.enable.len = 4;
   sniff.enable.data = enable ? P80211ENUM_truth_true : P80211ENUM_truth_false;

   sniff.channel.did = DIDmsg_lnxreq_wlansniff_channel;
   sniff.channel.len = 4;
   sniff.channel.data = channel;

   sniff.resultcode.did = DIDmsg_lnxreq_wlansniff_resultcode;
   sniff.resultcode.status = P80211ENUM_msgitem_status_no_value;
   sniff.resultcode.len = 4;

   /* get a socket */
   fd = socket(AF_INET, SOCK_STREAM, 0);

   if ( fd == -1 ) {
      return result;
   }
   ireq.u.data.pointer = (caddr_t) &sniff;   
   strcpy(ireq.ifr_ifrn.ifrn_name, dev);
   result = ioctl( fd, SIOCIWFIRSTPRIV + 0x8, &ireq);
   close(fd);

   if (result) {
      fprintf(stderr, "failed\n");
   }
   else {
      fprintf(stderr, "success\n");
   }
   return result;
}