iwlib.c

wireless tools: used to manipulate the Wireless Extensions. The Wireless Extensions is an interface

  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);
    }
}

/*------------------------------------------------------------------*/
/*
 * Output a frequency with proper scaling
 */
void
iw_print_freq(char *	buffer,
	      int	buflen,
	      double	freq,
	      int	channel,
	      int	freq_flags)
{
  char	sep = ((freq_flags & IW_FREQ_FIXED) ? '=' : ':');
  char	vbuf[16];

  /* Print the frequency/channel value */
  iw_print_freq_value(vbuf, sizeof(vbuf), freq);

  /* Check if channel only */
  if(freq < KILO)
    snprintf(buffer, buflen, "Channel%c%s", sep, vbuf);
  else
    {
      /* Frequency. Check if we have a channel as well */
      if(channel >= 0)
	snprintf(buffer, buflen, "Frequency%c%s (Channel %d)",
		 sep, vbuf, channel);
      else
	snprintf(buffer, buflen, "Frequency%c%s", sep, vbuf);
    }
}

/*------------------------------------------------------------------*/
/*
 * Convert a frequency to a channel (negative -> error)
 */
int
iw_freq_to_channel(double			freq,
		   const struct iw_range *	range)
{
  double	ref_freq;
  int		k;

  /* Check if it's a frequency or not already a channel */
  if(freq < KILO)
    return(-1);

  /* We compare the frequencies as double to ignore differences
   * in encoding. Slower, but safer... */
  for(k = 0; k < range->num_frequency; k++)
    {
      ref_freq = iw_freq2float(&(range->freq[k]));
      if(freq == ref_freq)
	return(range->freq[k].i);
    }
  /* Not found */
  return(-2);
}

/*------------------------------------------------------------------*/
/*
 * Convert a channel to a frequency (negative -> error)
 * Return the channel on success
 */
int
iw_channel_to_freq(int				channel,
		   double *			pfreq,
		   const struct iw_range *	range)
{
  int		has_freq = 0;
  int		k;

  /* Check if the driver support only channels or if it has frequencies */
  for(k = 0; k < range->num_frequency; k++)
    {
      if((range->freq[k].e != 0) || (range->freq[k].m > (int) KILO))
	has_freq = 1;
    }
  if(!has_freq)
    return(-1);

  /* Find the correct frequency in the list */
  for(k = 0; k < range->num_frequency; k++)
    {
      if(range->freq[k].i == channel)
	{
	  *pfreq = iw_freq2float(&(range->freq[k]));
	  return(channel);
	}
    }
  /* Not found */
  return(-2);
}

/*********************** BITRATE SUBROUTINES ***********************/

/*------------------------------------------------------------------*/
/*
 * Output a bitrate with proper scaling
 */
void
iw_print_bitrate(char *	buffer,
		 int	buflen,
		 int	bitrate)
{
  double	rate = bitrate;
  char		scale;
  int		divisor;

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

/************************ POWER SUBROUTINES *************************/

/*------------------------------------------------------------------*/
/*
 * Convert a value in dBm to a value in milliWatt.
 */
int
iw_dbm2mwatt(int	in)
{
#ifdef WE_NOLIBM
  /* Version without libm : slower */
  int		ip = in / 10;
  int		fp = in % 10;
  int		k;
  double	res = 1.0;

  /* Split integral and floating part to avoid accumulating rounding errors */
  for(k = 0; k < ip; k++)
    res *= 10;
  for(k = 0; k < fp; k++)
    res *= LOG10_MAGIC;
  return((int) res);
#else	/* WE_NOLIBM */
  /* Version with libm : faster */
  return((int) (floor(pow(10.0, (((double) in) / 10.0)))));
#endif	/* WE_NOLIBM */
}

/*------------------------------------------------------------------*/
/*
 * Convert a value in milliWatt to a value in dBm.
 */
int
iw_mwatt2dbm(int	in)
{
#ifdef WE_NOLIBM
  /* Version without libm : slower */
  double	fin = (double) in;
  int		res = 0;

  /* Split integral and floating part to avoid accumulating rounding errors */
  while(fin > 10.0)
    {
      res += 10;
      fin /= 10.0;
    }
  while(fin > 1.000001)	/* Eliminate rounding errors, take ceil */
    {
      res += 1;
      fin /= LOG10_MAGIC;
    }
  return(res);
#else	/* WE_NOLIBM */
  /* Version with libm : faster */
  return((int) (ceil(10.0 * log10((double) in))));
#endif	/* WE_NOLIBM */
}

/*------------------------------------------------------------------*/
/*
 * Output a txpower with proper conversion
 */
void
iw_print_txpower(char *			buffer,
		 int			buflen,
		 struct iw_param *	txpower)
{
  int		dbm;

  /* Check if disabled */
  if(txpower->disabled)
    {
      snprintf(buffer, buflen, "off");
    }
  else
    {
      /* Check for relative values */
      if(txpower->flags & IW_TXPOW_RELATIVE)
	{
	  snprintf(buffer, buflen, "%d", txpower->value);
	}
      else
	{
	  /* Convert everything to dBm */
	  if(txpower->flags & IW_TXPOW_MWATT)
	    dbm = iw_mwatt2dbm(txpower->value);
	  else
	    dbm = txpower->value;

	  /* Display */
	  snprintf(buffer, buflen, "%d dBm", dbm);
	}
    }
}

/********************** STATISTICS SUBROUTINES **********************/

/*------------------------------------------------------------------*/
/*
 * Read /proc/net/wireless to get the latest statistics
 * Note : strtok not thread safe, not used in WE-12 and later.
 */
int
iw_get_stats(int		skfd,
	     const char *	ifname,
	     iwstats *		stats,
	     const iwrange *	range,
	     int		has_range)
{
  /* Fortunately, we can always detect this condition properly */
  if((has_range) && (range->we_version_compiled > 11))
    {
      struct iwreq		wrq;
      wrq.u.data.pointer = (caddr_t) stats;
      wrq.u.data.length = sizeof(struct iw_statistics);
      wrq.u.data.flags = 1;		/* Clear updated flag */
      strncpy(wrq.ifr_name, ifname, IFNAMSIZ);
      if(iw_get_ext(skfd, ifname, SIOCGIWSTATS, &wrq) < 0)
	return(-1);

      /* Format has not changed since WE-12, no conversion */
      return(0);
    }
  else
    {
      FILE *	f = fopen(PROC_NET_WIRELESS, "r");
      char	buf[256];
      char *	bp;
      int	t;

      if(f==NULL)
	return -1;
      /* Loop on all devices */
      while(fgets(buf,255,f))
	{
	  bp=buf;
	  while(*bp&&isspace(*bp))
	    bp++;
	  /* Is it the good device ? */
	  if(strncmp(bp,ifname,strlen(ifname))==0 && bp[strlen(ifname)]==':')
	    {
	      /* Skip ethX: */
	      bp=strchr(bp,':');
	      bp++;
	      /* -- status -- */
	      bp = strtok(bp, " ");
	      sscanf(bp, "%X", &t);
	      stats->status = (unsigned short) t;
	      /* -- link quality -- */
	      bp = strtok(NULL, " ");
	      if(strchr(bp,'.') != NULL)
		stats->qual.updated |= 1;
	      sscanf(bp, "%d", &t);
	      stats->qual.qual = (unsigned char) t;
	      /* -- signal level -- */
	      bp = strtok(NULL, " ");
	      if(strchr(bp,'.') != NULL)
		stats->qual.updated |= 2;
	      sscanf(bp, "%d", &t);
	      stats->qual.level = (unsigned char) t;
	      /* -- noise level -- */
	      bp = strtok(NULL, " ");
	      if(strchr(bp,'.') != NULL)
		stats->qual.updated += 4;
	      sscanf(bp, "%d", &t);
	      stats->qual.noise = (unsigned char) t;
	      /* -- discarded packets -- */
	      bp = strtok(NULL, " ");
	      sscanf(bp, "%d", &stats->discard.nwid);
	      bp = strtok(NULL, " ");
	      sscanf(bp, "%d", &stats->discard.code);
	      bp = strtok(NULL, " ");
	      sscanf(bp, "%d", &stats->discard.misc);
	      fclose(f);
	      /* No conversion needed */
	      return 0;
	    }
	}
      fclose(f);
      return -1;
    }
}

/*------------------------------------------------------------------*/
/*
 * Output the link statistics, taking care of formating
 */
void
iw_print_stats(char *		buffer,
	       int		buflen,
	       const iwqual *	qual,
	       const iwrange *	range,
	       int		has_range)
{
  int		len;

  /* People are very often confused by the 8 bit arithmetic happening
   * here.
   * All the values here are encoded in a 8 bit integer. 8 bit integers
   * are either unsigned [0 ; 255], signed [-128 ; +127] or
   * negative [-255 ; 0].
   * Further, on 8 bits, 0x100 == 256 == 0.
   *
   * Relative/percent values are always encoded unsigned, between 0 and 255.
   * Absolute/dBm values are always encoded between -192 and 63.
   * (Note that up to version 28 of Wireless Tools, dBm used to be
   *  encoded always negative, between -256 and -1).
   *
   * How do we separate relative from absolute values ?
   * The old way is to use the range to do that. As of WE-19, we have
   * an explicit IW_QUAL_DBM flag in updated...
   * The range allow to specify the real min/max of the value. As the
   * range struct only specify one bound of the value, we assume that
   * the other bound is 0 (zero).
   * For relative values, range is [0 ; range->max].
   * For absolute values, range is [range->max ; 63].
   *
   * Let's take two example :
   * 1) value is 75%. qual->value = 75 ; range->max_qual.value = 100
   * 2) value is -54dBm. noise floor of the radio is -104dBm.
   *    qual->value = -54 = 202 ; range->max_qual.value = -104 = 152
   *
   * Jean II
   */

  /* Just do it...
   * The old way to detect dBm require both the range and a non-null
   * level (which confuse the test). The new way can deal with level of 0
   * because it does an explicit test on the flag. */
  if(has_range && ((qual->level != 0)
		   || (qual->updated & (IW_QUAL_DBM | IW_QUAL_RCPI))))
    {
      /* Deal with quality : always a relative value */
      if(!(qual->updated & IW_QUAL_QUAL_INVALID))
	{
	  len = snprintf(buffer, buflen, "Quality%c%d/%d  ",
			 qual->updated & IW_QUAL_QUAL_UPDATED ? '=' : ':',
			 qual->qual, range->max_qual.qual);
	  buffer += len;
	  buflen -= len;
	}

      /* Check if the statistics are in RCPI (IEEE 802.11k) */
      if(qual->updated & IW_QUAL_RCPI)
	{
	  /* Deal with signal level in RCPI */
	  /* RCPI = int{(Power in dBm +110)*2} for 0dbm > Power > -110dBm */
	  if(!(qual->updated & IW_QUAL_LEVEL_INVALID))
	    {
	      double	rcpilevel = (qual->level / 2.0) - 110.0;
	      len = snprintf(buffer, buflen, "Signal level%c%g dBm  ",
			     qual->updated & IW_QUAL_LEVEL_UPDATED ? '=' : ':',
			     rcpilevel);
	      buffer += len;
	      buflen -= len;
	    }

	  /* Deal with noise level in dBm (absolute power measurement) */
	  if(!(qual->updated & IW_QUAL_NOISE_INVALID))
	    {
	      double	rcpinoise = (qual->noise / 2.0) - 110.0;
	      len = snprintf(buffer, buflen, "Noise level%c%g dBm",
			     qual->updated & IW_QUAL_NOISE_UPDATED ? '=' : ':',
			     rcpinoise);
	    }
	}
      else
	{
	  /* Check if the statistics are in dBm */
	  if((qual->updated & IW_QUAL_DBM)
	     || (qual->level > range->max_qual.level))
	    {
	      /* Deal with signal level in dBm  (absolute power measurement) */
	      if(!(qual->updated & IW_QUAL_LEVEL_INVALID))
		{
		  int	dblevel = qual->level;
		  /* Implement a range for dBm [-192; 63] */
		  if(qual->level >= 64)
		    dblevel -= 0x100;
		  len = snprintf(buffer, buflen, "Signal level%c%d dBm  ",
				 qual->updated & IW_QUAL_LEVEL_UPDATED ? '=' : ':',
				 dblevel);
		  buffer += len;
		  buflen -= len;
		}

	      /* Deal with noise level in dBm (absolute power measurement) */
	      if(!(qual->updated & IW_QUAL_NOISE_INVALID))
		{
		  int	dbnoise = qual->noise;
		  /* Implement a range for dBm [-192; 63] */
		  if(qual->noise >= 64)
		    dbnoise -= 0x100;
		  len = snprintf(buffer, buflen, "Noise level%c%d dBm",
				 qual->updated & IW_QUAL_NOISE_UPDATED ? '=' : ':',
				 dbnoise);
		}
	    }
	  else
	    {
	      /* Deal with signal level as relative value (0 -> max) */
	      if(!(qual->updated & IW_QUAL_LEVEL_INVALID))
		{
		  len = snprintf(buffer, buflen, "Signal level%c%d/%d  ",
				 qual->updated & IW_QUAL_LEVEL_UPDATED ? '=' : ':',
				 qual->level, range->max_qual.level);
		  buffer += len;
		  buflen -= len;
		}

	      /* Deal with noise level as relative value (0 -> max) */
	      if(!(qual->updated & IW_QUAL_NOISE_INVALID))
		{
		  len = snprintf(buffer, buflen, "Noise level%c%d/%d",
				 qual->updated & IW_QUAL_NOISE_UPDATED ? '=' : ':',