net/ddns-scripts/files/usr/lib/ddns/dynamic_dns_updater.sh

   1 #!/bin/sh
   2 # /usr/lib/dynamic_dns/dynamic_dns_updater.sh
   3 #
   4 # Written by Eric Paul Bishop, Janary 2008
   5 # Distributed under the terms of the GNU General Public License (GPL) version 2.0
   6 #
   7 # This script is (loosely) based on the one posted by exobyte in the forums here:
   8 # http://forum.openwrt.org/viewtopic.php?id=14040
   9 #
  10
  11 . /usr/lib/ddns/dynamic_dns_functions.sh
  12 . /usr/lib/ddns/shell_get.sh
  13
  14
  15
  16
  17
  18
  19 service_id=$1
  20 if [ -z "$service_id" ]
  21 then
  22         echo "ERRROR: You must specify a service id (the section name in the /etc/config/ddns file) to initialize dynamic DNS."
  23         return 1
  24 fi
  25
  26 #default mode is verbose_mode, but easily turned off with second parameter
  27 verbose_mode="1"
  28 if [ -n "$2" ]
  29 then
  30         verbose_mode="$2"
  31 fi
  32
  33 ###############################################################
  34 # Leave this comment here, to clearly document variable names
  35 # that are expected/possible
  36 #
  37 # Now use load_all_config_options to load config
  38 # options, which is a much more flexible solution.
  39 #
  40 #
  41 #config_load "ddns"
  42 #
  43 #config_get enabled $service_id enabled
  44 #config_get service_name $service_id service_name
  45 #config_get update_url $service_id update_url
  46 #
  47 #
  48 #config_get username $service_id username
  49 #config_get password $service_id password
  50 #config_get domain $service_id domain
  51 #
  52 #
  53 #config_get ip_source $service_id ip_source
  54 #config_get ip_interface $service_id ip_interface
  55 #config_get ip_network $service_id ip_network
  56 #config_get ip_url $service_id ip_url
  57 #
  58 #config_get force_interval $service_id force_interval
  59 #config_get force_unit $service_id force_unit
  60 #
  61 #config_get check_interval $service_id check_interval
  62 #config_get check_unit $service_id check_unit
  63 #########################################################
  64 load_all_config_options "ddns" "$service_id"
  65
  66
  67 #some defaults
  68 if [ -z "$check_interval" ]
  69 then
  70         check_interval=600
  71 fi
  72
  73 if [ -z "$check_unit" ]
  74 then
  75         check_unit="seconds"
  76 fi
  77
  78
  79 if [ -z "$force_interval" ]
  80 then
  81         force_interval=72
  82 fi
  83
  84 if [ -z "$force_unit" ]
  85 then
  86         force_unit="hours"
  87 fi
  88
  89
  90
  91 #some constants
  92
  93 retrieve_prog="/usr/bin/wget --no-check-certificate -O - ";
  94 if [ -h "/usr/bin/wget" ]
  95 then
  96         busybox_wget=$(ls -l /usr/bin/wget | awk ' { if ($0~/busybox/) { print "BUSYBOX"}} ')
  97         if [ -n "$busybox_wget" ]; then
  98                 retrieve_prog="shell_get"
  99         fi
 100 fi
 101
 102 verbose_echo "retrieve_prog=\"$retrieve_prog\""
 103
 104 service_file="/usr/lib/ddns/services"
 105
 106 ip_regex="[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}"
 107
 108 NEWLINE_IFS='
 109 '
 110
 111
 112 #determine what update url we're using if the service_name is supplied
 113 if [ -n "$service_name" ]
 114 then
 115         #remove any lines not containing data, and then make sure fields are enclosed in double quotes
 116         quoted_services=$(cat $service_file |  grep "^[\t ]*[^#]" |  awk ' gsub("\x27", "\"") { if ($1~/^[^\"]*$/) $1="\""$1"\"" }; { if ( $NF~/^[^\"]*$/) $NF="\""$NF"\""  }; { print $0 }' )
 117
 118
 119         #echo "quoted_services = $quoted_services"
 120         OLD_IFS=$IFS
 121         IFS=$NEWLINE_IFS
 122         for service_line in $quoted_services
 123         do
 124                 #grep out proper parts of data and use echo to remove quotes
 125                 next_name=$(echo $service_line | grep -o "^[\t ]*\"[^\"]*\"" | xargs -r -n1 echo)
 126                 next_url=$(echo $service_line | grep -o "\"[^\"]*\"[\t ]*$" | xargs -r -n1 echo)
 127
 128                 if [ "$next_name" = "$service_name" ]
 129                 then
 130                         update_url=$next_url
 131                 fi
 132         done
 133         IFS=$OLD_IFS
 134 fi
 135
 136
 137
 138 verbose_echo "update_url=$update_url"
 139
 140
 141
 142 #if this service isn't enabled then quit
 143 if [ "$enabled" != "1" ]
 144 then
 145         return 0
 146 fi
 147
 148
 149
 150
 151
 152 #compute update interval in seconds
 153 case "$force_unit" in
 154         "days" )
 155                 force_interval_seconds=$(($force_interval*60*60*24))
 156                 ;;
 157         "hours" )
 158                 force_interval_seconds=$(($force_interval*60*60))
 159                 ;;
 160         "minutes" )
 161                 force_interval_seconds=$(($force_interval*60))
 162                 ;;
 163         "seconds" )
 164                 force_interval_seconds=$force_interval
 165                 ;;
 166         * )
 167                 #default is hours
 168                 force_interval_seconds=$(($force_interval*60*60))
 169                 ;;
 170 esac
 171
 172
 173
 174 #compute check interval in seconds
 175 case "$check_unit" in
 176         "days" )
 177                 check_interval_seconds=$(($check_interval*60*60*24))
 178                 ;;
 179         "hours" )
 180                 check_interval_seconds=$(($check_interval*60*60))
 181                 ;;
 182         "minutes" )
 183                 check_interval_seconds=$(($check_interval*60))
 184                 ;;
 185         "seconds" )
 186                 check_interval_seconds=$check_interval
 187                 ;;
 188         * )
 189                 #default is seconds
 190                 check_interval_seconds=$check_interval
 191                 ;;
 192 esac
 193
 194
 195
 196 verbose_echo "force seconds = $force_interval_seconds"
 197 verbose_echo "check seconds = $check_interval_seconds"
 198
 199 #kill old process if it exists & set new pid file
 200 if [ -d /var/run/dynamic_dns ]
 201 then
 202         #if process is already running, stop it
 203         if [ -e "/var/run/dynamic_dns/$service_id.pid" ]
 204         then
 205                 old_pid=$(cat /var/run/dynamic_dns/$service_id.pid)
 206                 test_match=$(ps | grep "^[\t ]*$old_pid")
 207                 verbose_echo "old process id (if it exists) = \"$test_match\""
 208                 if [ -n  "$test_match" ]
 209                 then
 210                         kill $old_pid
 211                 fi
 212         fi
 213
 214 else
 215         #make dir since it doesn't exist
 216         mkdir /var/run/dynamic_dns
 217 fi
 218 echo $$ > /var/run/dynamic_dns/$service_id.pid
 219
 220
 221
 222
 223 #determine when the last update was
 224 current_time=$(date +%s)
 225 last_update=$(( $current_time - (2*$force_interval_seconds) ))
 226 if [ -e "/var/run/dynamic_dns/$service_id.update" ]
 227 then
 228         last_update=$(cat /var/run/dynamic_dns/$service_id.update)
 229 fi
 230 time_since_update=$(($current_time - $last_update))
 231
 232
 233 human_time_since_update=$(( $time_since_update / ( 60 * 60 ) ))
 234 verbose_echo "time_since_update = $human_time_since_update hours"
 235
 236
 237
 238
 239 registered_ip=$(echo $(nslookup "$domain" 2>/dev/null) |  grep -o "Name:.*" | grep -o "$ip_regex")
 240
 241
 242 #do update and then loop endlessly, checking ip every check_interval and forcing an updating once every force_interval
 243
 244 while [ true ]
 245 do
 246         current_ip=$(get_current_ip)
 247
 248
 249         current_time=$(date +%s)
 250         time_since_update=$(($current_time - $last_update))
 251
 252
 253         verbose_echo "Running IP check..."
 254         verbose_echo "current system ip = $current_ip"
 255         verbose_echo "registered domain ip = $registered_ip"
 256
 257
 258         if [ "$current_ip" != "$registered_ip" ]  || [ $force_interval_seconds -lt $time_since_update ]
 259         then
 260                 verbose_echo "update necessary, performing update ..."
 261
 262                 #do replacement
 263                 final_url=$update_url
 264                 for option_var in $ALL_OPTION_VARIABLES
 265                 do
 266                         replace_name=$(echo "\[$option_var\]" | tr 'a-z' 'A-Z')
 267                         replace_value=$(eval echo "\$$option_var")
 268                         final_url=$(echo $final_url | sed s/"$replace_name"/"$replace_value"/g )
 269                 done
 270                 final_url=$(echo $final_url | sed s/"\[IP\]"/"$current_ip"/g )
 271
 272
 273                 verbose_echo "updating with url=\"$final_url\""
 274
 275                 #here we actually connect, and perform the update
 276                 update_output=$( $retrieve_prog "$final_url" )
 277
 278                 verbose_echo "Update Output:"
 279                 verbose_echo "$update_output"
 280                 verbose_echo ""
 281
 282                 #save the time of the update
 283                 current_time=$(date +%s)
 284                 last_update=$current_time
 285                 time_since_update='0'
 286                 registered_ip=$current_ip
 287
 288                 human_time=$(date)
 289                 verbose_echo "update complete, time is: $human_time"
 290
 291                 echo "$last_update" > "/var/run/dynamic_dns/$service_id.update"
 292         else
 293                 human_time=$(date)
 294                 human_time_since_update=$(( $time_since_update / ( 60 * 60 ) ))
 295                 verbose_echo "update unnecessary"
 296                 verbose_echo "time since last update = $human_time_since_update hours"
 297                 verbose_echo "the time is now $human_time"
 298         fi
 299
 300         #sleep for 10 minutes, then re-check ip && time since last update
 301         sleep $check_interval_seconds
 302 done
 303
 304 #should never get here since we're a daemon, but I'll throw it in anyway
 305 return 0
 306
 307
 308
 309