contrib/package/freifunk-watchdog/src/watchdog.c

   1 /*
   2  *   This program is free software; you can redistribute it and/or modify
   3  *   it under the terms of the GNU General Public License as published by
   4  *   the Free Software Foundation; either version 2 of the License, or
   5  *   (at your option) any later version.
   6  *
   7  *   This program is distributed in the hope that it will be useful,
   8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  *   GNU General Public License for more details.
  11  *
  12  *   You should have received a copy of the GNU General Public License
  13  *   along with this program; if not, write to the Free Software
  14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  15  *
  16  *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
  17  */
  18
  19 #include "watchdog.h"
  20
  21 /* Get BSSID of given interface */
  22 static int iw_get_bssid(int iwfd, const char *ifname, char *bssid)
  23 {
  24         struct iwreq iwrq;
  25
  26         if( iw_ioctl(iwfd, ifname, SIOCGIWAP, &iwrq) >= 0 )
  27         {
  28                 unsigned char *addr = (unsigned char *)iwrq.u.ap_addr.sa_data;
  29
  30                 sprintf(bssid, "%02X:%02X:%02X:%02X:%02X:%02X",
  31                         addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
  32
  33                 return 0;
  34         }
  35
  36         return -1;
  37 }
  38
  39 /* Get channel of given interface */
  40 static int iw_get_channel(int iwfd, const char *ifname, int *channel)
  41 {
  42         int i;
  43         char buffer[sizeof(struct iw_range)];
  44         double cur_freq, cmp_freq;
  45         struct iwreq iwrq;
  46         struct iw_range *range;
  47
  48         memset(buffer, 0, sizeof(buffer));
  49
  50         iwrq.u.data.pointer = (char *)buffer;
  51         iwrq.u.data.length = sizeof(buffer);
  52         iwrq.u.data.flags = 0;
  53
  54         if( iw_ioctl(iwfd, ifname, SIOCGIWRANGE, &iwrq) < 0)
  55         {
  56                 *channel = -1;
  57                 return -1;
  58         }
  59
  60         range = (struct iw_range *)buffer;
  61
  62         if( iw_ioctl(iwfd, ifname, SIOCGIWFREQ, &iwrq) >= 0 )
  63         {
  64                 cur_freq = ((double)iwrq.u.freq.m) * pow(10, iwrq.u.freq.e);
  65                 if( cur_freq < 1000.00 )
  66                 {
  67                         *channel = (int)cur_freq;
  68                         return 0;
  69                 }
  70
  71                 for(i = 0; i < range->num_frequency; i++)
  72             {
  73                         cmp_freq = ((double)range->freq[i].m) * pow(10, range->freq[i].e);
  74                         if( cmp_freq == cur_freq )
  75                         {
  76                                 *channel = (int)range->freq[i].i;
  77                                 return 0;
  78                         }
  79                 }
  80         }
  81
  82         *channel = -1;
  83         return -1;
  84 }
  85
  86 /* Get the (first) pid of given process name */
  87 static int find_process(const char *name)
  88 {
  89         int pid = -1;
  90         int file;
  91         char buffer[128];
  92         char cmpname[128];
  93         DIR *dir;
  94         struct dirent *entry;
  95
  96         if( (dir = opendir("/proc")) != NULL )
  97         {
  98                 snprintf(cmpname, sizeof(cmpname), "Name:\t%s\n", name);
  99
 100                 while( (entry = readdir(dir)) != NULL )
 101                 {
 102                         if( !strcmp(entry->d_name, "..") || !isdigit(*entry->d_name) )
 103                                 continue;
 104
 105                         sprintf(buffer, "/proc/%s/status", entry->d_name);
 106                         if( (file = open(buffer, O_RDONLY)) > -1 )
 107                         {
 108                                 read(file, buffer, sizeof(buffer));
 109                                 close(file);
 110
 111                                 if( strstr(buffer, cmpname) == buffer )
 112                                 {
 113                                         pid = atoi(entry->d_name);
 114                                         break;
 115                                 }
 116                         }
 117                 }
 118
 119                 closedir(dir);
 120                 return pid;
 121         }
 122
 123         syslog(LOG_CRIT, "Unable to open /proc: %s",
 124                 strerror(errno));
 125
 126         return -1;
 127 }
 128
 129 /* Check if given uci file was updated */
 130 static int check_uci_update(const char *config, time_t *mtime)
 131 {
 132         struct stat s;
 133         char path[128];
 134
 135         snprintf(path, sizeof(path), "/etc/config/%s", config);
 136         if( stat(path, &s) > -1 )
 137         {
 138                 if( (*mtime == 0) || (s.st_mtime > *mtime) )
 139                 {
 140                         *mtime = s.st_mtime;
 141                         return 1;
 142                 }
 143                 else
 144                 {
 145                         snprintf(path, sizeof(path), "/var/state/%s", config);
 146                         if( stat(path, &s) > -1 )
 147                         {
 148                                 if( (*mtime == 0) || (s.st_mtime > *mtime) )
 149                                 {
 150                                         *mtime = s.st_mtime;
 151                                         return 1;
 152                                 }
 153                         }
 154
 155                         return 0;
 156                 }
 157         }
 158
 159         return -1;
 160 }
 161
 162 /* Add tuple */
 163 static void load_wifi_uci_add_iface(const char *section, struct uci_itr_ctx *itr)
 164 {
 165         wifi_tuple_t *t;
 166         const char *ucitmp;
 167         int val = 0;
 168
 169         if( (t = (wifi_tuple_t *)malloc(sizeof(wifi_tuple_t))) != NULL )
 170         {
 171                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "ifname");
 172                 if(ucitmp)
 173                 {
 174                         strncpy(t->ifname, ucitmp, sizeof(t->ifname));
 175                         val++;
 176                 }
 177
 178                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "bssid");
 179                 if(ucitmp)
 180                 {
 181                         strncpy(t->bssid, ucitmp, sizeof(t->bssid));
 182                         val++;
 183                 }
 184
 185                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "device");
 186                 if(ucitmp)
 187                 {
 188                         ucitmp = ucix_get_option(itr->ctx, "wireless", ucitmp, "channel");
 189                         if(ucitmp)
 190                         {
 191                                 t->channel = atoi(ucitmp);
 192                                 val++;
 193                         }
 194                 }
 195
 196                 if( val == 3 )
 197                 {
 198                         syslog(LOG_INFO, "Monitoring %s: bssid=%s channel=%d",
 199                                 t->ifname, t->bssid, t->channel);
 200
 201                         t->next = itr->list;
 202                         itr->list = t;
 203                 }
 204                 else
 205                 {
 206                         free(t);
 207                 }
 208         }
 209 }
 210
 211 /* Load config */
 212 static wifi_tuple_t * load_wifi_uci(wifi_tuple_t *ifs, time_t *modtime)
 213 {
 214         struct uci_context *ctx;
 215         struct uci_itr_ctx itr;
 216         wifi_tuple_t *cur, *next;
 217
 218         if( check_uci_update("wireless", modtime) )
 219         {
 220                 syslog(LOG_INFO, "Config changed, reloading");
 221
 222                 if( (ctx = ucix_init("wireless")) != NULL )
 223                 {
 224                         if( ifs != NULL )
 225                         {
 226                                 for(cur = ifs; cur; cur = next)
 227                                 {
 228                                         next = cur->next;
 229                                         free(cur);
 230                                 }
 231                         }
 232
 233                         itr.list = NULL;
 234                         itr.ctx = ctx;
 235
 236                         ucix_for_each_section_type(ctx, "wireless", "wifi-iface",
 237                                 (void *)load_wifi_uci_add_iface, &itr);
 238
 239                         return itr.list;
 240                 }
 241         }
 242
 243         return ifs;
 244 }
 245
 246 /* Daemon implementation */
 247 static int do_daemon(void)
 248 {
 249         int iwfd;
 250         int channel;
 251         char bssid[18];
 252
 253         wifi_tuple_t *ifs = NULL, *curif;
 254         time_t modtime = 0;
 255
 256         int restart_wifi = 0;
 257         int restart_cron = 0;
 258
 259         openlog(SYSLOG_IDENT, 0, LOG_DAEMON);
 260         //daemon(1, 1);
 261
 262         if( (iwfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
 263         {
 264                 perror("Can not open wireless control socket");
 265                 return 1;
 266         }
 267
 268         while( 1 )
 269         {
 270                 if( (ifs = load_wifi_uci(ifs, &modtime)) == NULL )
 271                 {
 272                         printf("Can not load wireless uci. File corrupt?\n");
 273                         return 1;
 274                 }
 275
 276                 /* Check crond */
 277                 if( find_process("crond") < 0 )
 278                 {
 279                         syslog(LOG_WARNING, "The crond process died, restarting");
 280                         restart_cron++;
 281                 }
 282
 283                 /* Check wireless interfaces */
 284                 for( curif = ifs; curif; curif = curif->next )
 285                 {
 286                         /* Get current channel and bssid */
 287                         if( (iw_get_bssid(iwfd, curif->ifname, bssid) == 0) &&
 288                             (iw_get_channel(iwfd, curif->ifname, &channel) == 0) )
 289                         {
 290                                 /* Check BSSID */
 291                                 if( strcasecmp(bssid, curif->bssid) != 0 )
 292                                 {
 293                                         syslog(LOG_WARNING, "BSSID mismatch on %s: current=%s wanted=%s",
 294                                                 curif->ifname, bssid, curif->bssid);
 295
 296                                         restart_wifi++;
 297                                 }
 298
 299                                 /* Check channel */
 300                                 if( channel != curif->channel )
 301                                 {
 302                                         syslog(LOG_WARNING, "Channel mismatch on %s: current=%d wanted=%d",
 303                                                 curif->ifname, channel, curif->channel);
 304
 305                                         restart_wifi++;
 306                                 }
 307                         }
 308                         else
 309                         {
 310                                 syslog(LOG_WARNING, "Requested interface %s not present", curif->ifname);
 311                         }
 312                 }
 313
 314
 315                 /* Wifi restart required? */
 316                 if( restart_wifi > 0 )
 317                 {
 318                         restart_wifi = 0;
 319                         EXEC(WIFI_ACTION);
 320                 }
 321
 322                 /* Cron restart required? */
 323                 if( restart_cron > 0 )
 324                 {
 325                         restart_cron = 0;
 326                         EXEC(CRON_ACTION);
 327                 }
 328
 329                 sleep(INTERVAL);
 330         }
 331
 332         closelog();
 333         return 0;
 334 }
 335
 336
 337 int main(int argc, char *argv[])
 338 {
 339         /* Check if watchdog is running ... */
 340         if( (argc > 1) && (strcmp(argv[1], "running") == 0) )
 341         {
 342                 return (find_process(BINARY) >= 0);
 343         }
 344
 345         /* Start daemon */
 346         return do_daemon();
 347 }