src/wireless.c

   1 /**
   2  * collectd - src/wireless.c
   3  * Copyright (C) 2006  Florian octo Forster
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  18  *
  19  * Author:
  20  *   Florian octo Forster <octo at verplant.org>
  21  **/
  22
  23 #include "collectd.h"
  24 #include "common.h"
  25 #include "plugin.h"
  26
  27 #include <math.h>
  28
  29 #define MODULE_NAME "wireless"
  30 #define BUFSIZE 1024
  31
  32 #if defined(KERNEL_LINUX)
  33 # define WIRELESS_HAVE_READ 1
  34 #else
  35 # define WIRELESS_HAVE_READ 0
  36 #endif
  37
  38 #define WIRELESS_PROC_FILE "/proc/net/wireless"
  39
  40 static char *filename_template = "wireless-%s.rrd";
  41
  42 static char *ds_def[] =
  43 {
  44         "DS:quality:GAUGE:"COLLECTD_HEARTBEAT":0:U",
  45         "DS:power:GAUGE:"COLLECTD_HEARTBEAT":0:U",
  46         "DS:noise:GAUGE:"COLLECTD_HEARTBEAT":0:U",
  47         NULL
  48 };
  49 static int ds_num = 3;
  50
  51 #if WIRELESS_HAVE_READ
  52 static int proc_file_found = 0;
  53 #endif
  54
  55 static void wireless_init (void)
  56 {
  57 #if WIRELESS_HAVE_READ
  58         if (access (WIRELESS_PROC_FILE, R_OK) == 0)
  59                 proc_file_found = 1;
  60         else
  61                 proc_file_found = 0;
  62 #endif
  63
  64         return;
  65 }
  66
  67 static void wireless_write (char *host, char *inst, char *val)
  68 {
  69         char file[BUFSIZE];
  70         int status;
  71
  72         status = snprintf (file, BUFSIZE, filename_template, inst);
  73         if (status < 1)
  74                 return;
  75         else if (status >= BUFSIZE)
  76                 return;
  77
  78         rrd_update_file (host, file, val, ds_def, ds_num);
  79 }
  80
  81 #if WIRELESS_HAVE_READ
  82 static double wireless_dbm_to_watt (double dbm)
  83 {
  84         double watt;
  85
  86         /*
  87          * dbm = 10 * log_{10} (1000 * power / W)
  88          * power = 10^(dbm/10) * W/1000
  89          */
  90
  91         watt = pow (10.0, (dbm / 10.0)) / 1000.0;
  92
  93         return (watt);
  94 }
  95
  96 static void wireless_submit (char *device,
  97                 double quality, double power, double noise)
  98 {
  99         char buf[BUFSIZE];
 100         int  status;
 101
 102         status = snprintf (buf, BUFSIZE, "%u:%f:%f:%f",
 103                         (unsigned int) curtime,
 104                         quality, power, noise);
 105         if ((status < 1) || (status >= BUFSIZE))
 106                 return;
 107
 108         plugin_submit (MODULE_NAME, device, buf);
 109 }
 110
 111 static void wireless_read (void)
 112 {
 113 #ifdef KERNEL_LINUX
 114
 115         FILE *fh;
 116         char buffer[BUFSIZE];
 117
 118         char   *device;
 119         double  quality;
 120         double  power;
 121         double  noise;
 122
 123         char *fields[8];
 124         int   numfields;
 125
 126         int len;
 127
 128         if (!proc_file_found)
 129                 return;
 130
 131         /* there are a variety of names for the wireless device */
 132         if ((fh = fopen (WIRELESS_PROC_FILE, "r")) == NULL)
 133         {
 134                 syslog (LOG_WARNING, "wireless: fopen: %s", strerror (errno));
 135                 return;
 136         }
 137
 138         while (fgets (buffer, BUFSIZE, fh) != NULL)
 139         {
 140                 numfields = strsplit (buffer, fields, 8);
 141
 142                 if (numfields < 5)
 143                         continue;
 144
 145                 len = strlen (fields[0]) - 1;
 146                 if (len < 1)
 147                         continue;
 148                 if (fields[0][len] != ':')
 149                         continue;
 150                 fields[0][len] = '\0';
 151
 152                 device  = fields[0];
 153                 quality = atof (fields[2]);
 154                 power   = atof (fields[3]);
 155                 noise   = atof (fields[4]);
 156
 157                 if (quality == 0.0)
 158                         quality = -1.0;
 159
 160                 if (power >= 0.0)
 161                         power = -1.0;
 162                 else
 163                         power = wireless_dbm_to_watt (power);
 164
 165                 if (noise >= 0.0)
 166                         noise = -1.0;
 167                 else
 168                         noise = wireless_dbm_to_watt (noise);
 169
 170                 wireless_submit (device, quality, power, noise);
 171         }
 172
 173         fclose (fh);
 174 #endif /* KERNEL_LINUX */
 175 }
 176 #else
 177 # define wireless_read NULL
 178 #endif /* WIRELESS_HAVE_READ */
 179
 180 void module_register (void)
 181 {
 182    plugin_register (MODULE_NAME, wireless_init, wireless_read, wireless_write);
 183 }
 184
 185 #undef BUFSIZE
 186 #undef MODULE_NAME