iwlib.c

This package contains the Wireless tools, used to manipulate the Wireless Extensions. The Wireless

	     iwr15_off(txpower) - iwr15_off(txpower_capa));
      /* Hum... That's an unexpected glitch. Bummer. */
      memcpy((char *) range + iwr_off(txpower),
	     buffer + iwr15_off(txpower),
	     iwr15_off(avg_qual) - iwr15_off(txpower));
      /* Avg qual moved up next to max_qual */
      memcpy((char *) range + iwr_off(avg_qual),
	     buffer + iwr15_off(avg_qual),
	     sizeof(struct iw_quality));
    }

  /* We are now checking much less than we used to do, because we can
   * accomodate more WE version. But, there are still cases where things
   * will break... */
  if(!iw_ignore_version)
    {
      /* We don't like very old version (unfortunately kernel 2.2.X) */
      if(range->we_version_compiled <= 10)
	{
	  fprintf(stderr, "Warning: Driver for device %s has been compiled with an ancient version\n", ifname);
	  fprintf(stderr, "of Wireless Extension, while this program support version 11 and later.\n");
	  fprintf(stderr, "Some things may be broken...\n\n");
	}

      /* We don't like future versions of WE, because we can't cope with
       * the unknown */
      if(range->we_version_compiled > WE_MAX_VERSION)
	{
	  fprintf(stderr, "Warning: Driver for device %s has been compiled with version %d\n", ifname, range->we_version_compiled);
	  fprintf(stderr, "of Wireless Extension, while this program supports up to version %d.\n", WE_VERSION);
	  fprintf(stderr, "Some things may be broken...\n\n");
	}

      /* Driver version verification */
      if((range->we_version_compiled > 10) &&
	 (range->we_version_compiled < range->we_version_source))
	{
	  fprintf(stderr, "Warning: Driver for device %s recommend version %d of Wireless Extension,\n", ifname, range->we_version_source);
	  fprintf(stderr, "but has been compiled with version %d, therefore some driver features\n", range->we_version_compiled);
	  fprintf(stderr, "may not be available...\n\n");
	}
      /* Note : we are only trying to catch compile difference, not source.
       * If the driver source has not been updated to the latest, it doesn't
       * matter because the new fields are set to zero */
    }

  /* Don't complain twice.
   * In theory, the test apply to each individual driver, but usually
   * all drivers are compiled from the same kernel. */
  iw_ignore_version = 1;

  return(0);
}

/*------------------------------------------------------------------*/
/*
 * Get information about what private ioctls are supported by the driver
 *
 * Note : there is one danger using this function. If it return 0, you
 * still need to free() the buffer. Beware.
 */
int
iw_get_priv_info(int		skfd,
		 const char *	ifname,
		 iwprivargs **	ppriv)
{
  struct iwreq		wrq;
  iwprivargs *		priv = NULL;	/* Not allocated yet */
  int			maxpriv = 16;	/* Minimum for compatibility WE<13 */
  iwprivargs *		newpriv;

  /* Some driver may return a very large number of ioctls. Some
   * others a very small number. We now use a dynamic allocation
   * of the array to satisfy everybody. Of course, as we don't know
   * in advance the size of the array, we try various increasing
   * sizes. Jean II */
  do
    {
      /* (Re)allocate the buffer */
      newpriv = realloc(priv, maxpriv * sizeof(priv[0]));
      if(newpriv == NULL)
	{
	  fprintf(stderr, "%s: Allocation failed\n", __FUNCTION__);
	  break;
	}
      priv = newpriv;

      /* Ask the driver if it's large enough */
      wrq.u.data.pointer = (caddr_t) priv;
      wrq.u.data.length = maxpriv;
      wrq.u.data.flags = 0;
      if(iw_get_ext(skfd, ifname, SIOCGIWPRIV, &wrq) >= 0)
	{
	  /* Success. Pass the buffer by pointer */
	  *ppriv = priv;
	  /* Return the number of ioctls */
	  return(wrq.u.data.length);
	}

      /* Only E2BIG means the buffer was too small, abort on other errors */
      if(errno != E2BIG)
	{
	  /* Most likely "not supported". Don't barf. */
	  break;
	}

      /* Failed. We probably need a bigger buffer. Check if the kernel
       * gave us any hints. */
      if(wrq.u.data.length > maxpriv)
	maxpriv = wrq.u.data.length;
      else
	maxpriv *= 2;
    }
  while(maxpriv < 1000);

  /* Cleanup */
  if(priv)
    free(priv);
  *ppriv = NULL;

  return(-1);
}

/*------------------------------------------------------------------*/
/*
 * Get essential wireless config from the device driver
 * We will call all the classical wireless ioctl on the driver through
 * the socket to know what is supported and to get the settings...
 * Note : compare to the version in iwconfig, we extract only
 * what's *really* needed to configure a device...
 */
int
iw_get_basic_config(int			skfd,
		    const char *	ifname,
		    wireless_config *	info)
{
  struct iwreq		wrq;

  memset((char *) info, 0, sizeof(struct wireless_config));

  /* Get wireless name */
  if(iw_get_ext(skfd, ifname, SIOCGIWNAME, &wrq) < 0)
    /* If no wireless name : no wireless extensions */
    return(-1);
  else
    {
      strncpy(info->name, wrq.u.name, IFNAMSIZ);
      info->name[IFNAMSIZ] = '\0';
    }

  /* Get network ID */
  if(iw_get_ext(skfd, ifname, SIOCGIWNWID, &wrq) >= 0)
    {
      info->has_nwid = 1;
      memcpy(&(info->nwid), &(wrq.u.nwid), sizeof(iwparam));
    }

  /* Get frequency / channel */
  if(iw_get_ext(skfd, ifname, SIOCGIWFREQ, &wrq) >= 0)
    {
      info->has_freq = 1;
      info->freq = iw_freq2float(&(wrq.u.freq));
      info->freq_flags = wrq.u.freq.flags;
    }

  /* Get encryption information */
  wrq.u.data.pointer = (caddr_t) info->key;
  wrq.u.data.length = IW_ENCODING_TOKEN_MAX;
  wrq.u.data.flags = 0;
  if(iw_get_ext(skfd, ifname, SIOCGIWENCODE, &wrq) >= 0)
    {
      info->has_key = 1;
      info->key_size = wrq.u.data.length;
      info->key_flags = wrq.u.data.flags;
    }

  /* Get ESSID */
  wrq.u.essid.pointer = (caddr_t) info->essid;
  wrq.u.essid.length = IW_ESSID_MAX_SIZE + 1;
  wrq.u.essid.flags = 0;
  if(iw_get_ext(skfd, ifname, SIOCGIWESSID, &wrq) >= 0)
    {
      info->has_essid = 1;
      info->essid_on = wrq.u.data.flags;
    }

  /* Get operation mode */
  if(iw_get_ext(skfd, ifname, SIOCGIWMODE, &wrq) >= 0)
    {
      info->mode = wrq.u.mode;
      if((info->mode < IW_NUM_OPER_MODE) && (info->mode >= 0))
	info->has_mode = 1;
    }

  return(0);
}

/*------------------------------------------------------------------*/
/*
 * Set essential wireless config in the device driver
 * We will call all the classical wireless ioctl on the driver through
 * the socket to know what is supported and to set the settings...
 * We support only the restricted set as above...
 */
int
iw_set_basic_config(int			skfd,
		    const char *	ifname,
		    wireless_config *	info)
{
  struct iwreq		wrq;
  int			ret = 0;

  /* Get wireless name (check if interface is valid) */
  if(iw_get_ext(skfd, ifname, SIOCGIWNAME, &wrq) < 0)
    /* If no wireless name : no wireless extensions */
    return(-2);

  /* Set the current mode of operation
   * Mode need to be first : some settings apply only in a specific mode
   * (such as frequency).
   */
  if(info->has_mode)
    {
      strncpy(wrq.ifr_name, ifname, IFNAMSIZ);
      wrq.u.mode = info->mode;

      if(iw_get_ext(skfd, ifname, SIOCSIWMODE, &wrq) < 0)
	{
	  fprintf(stderr, "SIOCSIWMODE: %s\n", strerror(errno));
	  ret = -1;
	}
    }

  /* Set frequency / channel */
  if(info->has_freq)
    {
      iw_float2freq(info->freq, &(wrq.u.freq));

      if(iw_set_ext(skfd, ifname, SIOCSIWFREQ, &wrq) < 0)
	{
	  fprintf(stderr, "SIOCSIWFREQ: %s\n", strerror(errno));
	  ret = -1;
	}
    }

  /* Set encryption information */
  if(info->has_key)
    {
      int		flags = info->key_flags;

      /* Check if there is a key index */
      if((flags & IW_ENCODE_INDEX) > 0)
	{
	  /* Set the index */
	  wrq.u.data.pointer = (caddr_t) NULL;
	  wrq.u.data.flags = (flags & (IW_ENCODE_INDEX)) | IW_ENCODE_NOKEY;
	  wrq.u.data.length = 0;

	  if(iw_set_ext(skfd, ifname, SIOCSIWENCODE, &wrq) < 0)
	    {
	      fprintf(stderr, "SIOCSIWENCODE(%d): %s\n",
		      errno, strerror(errno));
	      ret = -1;
	    }
	}

      /* Mask out index to minimise probability of reject when setting key */
      flags = flags & (~IW_ENCODE_INDEX);

      /* Set the key itself (set current key in this case) */
      wrq.u.data.pointer = (caddr_t) info->key;
      wrq.u.data.length = info->key_size;
      wrq.u.data.flags = flags;

      /* Compatibility with WE<13 */
      if(flags & IW_ENCODE_NOKEY)
	wrq.u.data.pointer = NULL;

      if(iw_set_ext(skfd, ifname, SIOCSIWENCODE, &wrq) < 0)
	{
	  fprintf(stderr, "SIOCSIWENCODE(%d): %s\n",
		  errno, strerror(errno));
	  ret = -1;
	}
    }

  /* Set Network ID, if available (this is for non-802.11 cards) */
  if(info->has_nwid)
    {
      memcpy(&(wrq.u.nwid), &(info->nwid), sizeof(iwparam));
      wrq.u.nwid.fixed = 1;	/* Hum... When in Rome... */

      if(iw_set_ext(skfd, ifname, SIOCSIWNWID, &wrq) < 0)
	{
	  fprintf(stderr, "SIOCSIWNWID: %s\n", strerror(errno));
	  ret = -1;
	}
    }

  /* Set ESSID (extended network), if available.
   * ESSID need to be last : most device re-perform the scanning/discovery
   * when this is set, and things like encryption keys are better be
   * defined if we want to discover the right set of APs/nodes.
   */
  if(info->has_essid)
    {
      int		we_kernel_version;
      we_kernel_version = iw_get_kernel_we_version();

      wrq.u.essid.pointer = (caddr_t) info->essid;
      wrq.u.essid.length = strlen(info->essid) + 1;
      wrq.u.data.flags = info->essid_on;
      if(we_kernel_version > 20)
	wrq.u.essid.length--;

      if(iw_set_ext(skfd, ifname, SIOCSIWESSID, &wrq) < 0)
	{
	  fprintf(stderr, "SIOCSIWESSID: %s\n", strerror(errno));
	  ret = -1;
	}
    }

  return(ret);
}

/*********************** PROTOCOL SUBROUTINES ***********************/
/*
 * Fun stuff with protocol identifiers (SIOCGIWNAME).
 * We assume that drivers are returning sensible values in there,
 * which is not always the case :-(
 */

/*------------------------------------------------------------------*/
/*
 * Compare protocol identifiers.
 * We don't want to know if the two protocols are the exactly same,
 * but if they interoperate at some level, and also if they accept the
 * same type of config (ESSID vs NWID, freq...).
 * This is supposed to work around the alphabet soup.
 * Return 1 if protocols are compatible, 0 otherwise
 */
int
iw_protocol_compare(const char *	protocol1,
		    const char *	protocol2)
{
  const char *	dot11 = "IEEE 802.11";
  const char *	dot11_ds = "Dbg";
  const char *	dot11_5g = "a";

  /* If the strings are the same -> easy */
  if(!strncmp(protocol1, protocol2, IFNAMSIZ))
    return(1);

  /* Are we dealing with one of the 802.11 variant ? */
  if( (!strncmp(protocol1, dot11, strlen(dot11))) &&
      (!strncmp(protocol2, dot11, strlen(dot11))) )
    {
      const char *	sub1 = protocol1 + strlen(dot11);
      const char *	sub2 = protocol2 + strlen(dot11);
      unsigned int	i;
      int		isds1 = 0;
      int		isds2 = 0;
      int		is5g1 = 0;
      int		is5g2 = 0;

      /* Check if we find the magic letters telling it's DS compatible */
      for(i = 0; i < strlen(dot11_ds); i++)
	{
	  if(strchr(sub1, dot11_ds[i]) != NULL)
	    isds1 = 1;
	  if(strchr(sub2, dot11_ds[i]) != NULL)
	    isds2 = 1;
	}
      if(isds1 && isds2)
	return(1);

      /* Check if we find the magic letters telling it's 5GHz compatible */
      for(i = 0; i < strlen(dot11_5g); i++)
	{
	  if(strchr(sub1, dot11_5g[i]) != NULL)
	    is5g1 = 1;
	  if(strchr(sub2, dot11_5g[i]) != NULL)
	    is5g2 = 1;
	}
      if(is5g1 && is5g2)
	return(1);
    }
  /* Not compatible */
  return(0);
}

/********************** FREQUENCY SUBROUTINES ***********************/
/*
 * Note : the two functions below are the cause of troubles on
 * various embeeded platforms, as they are the reason we require
 * libm (math library).
 * In this case, please use enable BUILD_NOLIBM in the makefile
 *
 * FIXME : check negative mantissa and exponent
 */

/*------------------------------------------------------------------*/
/*
 * Convert a floating point the our internal representation of
 * frequencies.
 * The kernel doesn't want to hear about floating point, so we use
 * this custom format instead.
 */
void
iw_float2freq(double	in,
	      iwfreq *	out)
{
#ifdef WE_NOLIBM
  /* Version without libm : slower */
  out->e = 0;
  while(in > 1e9)
    {
      in /= 10;
      out->e++;
    }
  out->m = (long) in;
#else	/* WE_NOLIBM */
  /* Version with libm : faster */
  out->e = (short) (floor(log10(in)));
  if(out->e > 8)
    {
      out->m = ((long) (floor(in / pow(10,out->e - 6)))) * 100;
      out->e -= 8;
    }
  else
    {
      out->m = (long) in;
      out->e = 0;
    }
#endif	/* WE_NOLIBM */
}

/*------------------------------------------------------------------*/
/*
 * Convert our internal representation of frequencies to a floating point.
 */
double
iw_freq2float(const iwfreq *	in)
{
#ifdef WE_NOLIBM
  /* Version without libm : slower */
  int		i;
  double	res = (double) in->m;
  for(i = 0; i < in->e; i++)
    res *= 10;
  return(res);
#else	/* WE_NOLIBM */
  /* Version with libm : faster */
  return ((double) in->m) * pow(10,in->e);
#endif	/* WE_NOLIBM */
}

/*------------------------------------------------------------------*/
/*
 * Output a frequency with proper scaling
 */
void
iw_print_freq_value(char *	buffer,
		    int		buflen,
		    double	freq)
{
  if(freq < KILO)
    snprintf(buffer, buflen, "%g", freq);
  else
    {
      char	scale;
      int	divisor;

      if(freq >= GIGA)
	{
	  scale = 'G';
	  divisor = GIGA;
	}
      else
	{
	  if(freq >= MEGA)
	    {
	      scale = 'M';
	      divisor = MEGA;
	    }
	  else
	    {
	      scale = 'k';
	      divisor = KILO;
	    }
	}
      snprintf(buffer, buflen, "%g %cHz", freq / divisor, scale);
    }
}