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
  13
  14 service_id=$1
  15 if [ -z "$service_id" ]
  16 then
  17         echo "ERRROR: You must specify a service id (the section name in the /etc/config/ddns file) to initialize dynamic DNS."
  18         return 1
  19 fi
  20
  21 #default mode is verbose_mode, but easily turned off with second parameter
  22 verbose_mode="1"
  23 if [ -n "$2" ]
  24 then
  25         verbose_mode="$2"
  26 fi
  27
  28 ###############################################################
  29 # Leave this comment here, to clearly document variable names
  30 # that are expected/possible
  31 #
  32 # Now use load_all_config_options to load config
  33 # options, which is a much more flexible solution.
  34 #
  35 #
  36 #config_load "ddns"
  37 #
  38 #config_get enabled $service_id enabled
  39 #config_get service_name $service_id service_name
  40 #config_get update_url $service_id update_url
  41 #
  42 #
  43 #config_get username $service_id username
  44 #config_get password $service_id password
  45 #config_get domain $service_id domain
  46 #
  47 #
  48 #config_get ip_source $service_id ip_source
  49 #config_get ip_interface $service_id ip_interface
  50 #config_get ip_network $service_id ip_network
  51 #config_get ip_url $service_id ip_url
  52 #
  53 #config_get force_interval $service_id force_interval
  54 #config_get force_unit $service_id force_unit
  55 #
  56 #config_get check_interval $service_id check_interval
  57 #config_get check_unit $service_id check_unit
  58 #########################################################
  59 load_all_config_options "ddns" "$service_id"
  60
  61
  62 #some defaults
  63 if [ -z "$check_interval" ]
  64 then
  65         check_interval=600
  66 fi
  67
  68 if [ -z "$check_unit" ]
  69 then
  70         check_unit="seconds"
  71 fi
  72
  73
  74 if [ -z "$force_interval" ]
  75 then
  76         force_interval=72
  77 fi
  78
  79 if [ -z "$force_unit" ]
  80 then
  81         force_unit="hours"
  82 fi
  83
  84
  85
  86 #some constants
  87
  88 retrieve_prog="/usr/bin/wget -O - ";
  89 service_file="/usr/lib/ddns/services"
  90
  91 ip_regex="[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}"
  92
  93 NEWLINE_IFS='
  94 '
  95
  96
  97 #determine what update url we're using if the service_name is supplied
  98 if [ -n "$service_name" ]
  99 then
 100         #remove any lines not containing data, and then make sure fields are enclosed in double quotes
 101         quoted_services=$(cat $service_file |  grep "^[\t ]*[^#]" |  awk ' gsub("\x27", "\"") { if ($1~/^[^\"]*$/) $1="\""$1"\"" }; { if ( $NF~/^[^\"]*$/) $NF="\""$NF"\""  }; { print $0 }' )
 102
 103
 104         #echo "quoted_services = $quoted_services"
 105         OLD_IFS=$IFS
 106         IFS=$NEWLINE_IFS
 107         for service_line in $quoted_services
 108         do
 109                 #grep out proper parts of data and use echo to remove quotes
 110                 next_name=$(echo $service_line | grep -o "^[\t ]*\"[^\"]*\"" | xargs -r -n1 echo)
 111                 next_url=$(echo $service_line | grep -o "\"[^\"]*\"[\t ]*$" | xargs -r -n1 echo)
 112
 113                 if [ "$next_name" = "$service_name" ]
 114                 then
 115                         update_url=$next_url
 116                 fi
 117         done
 118         IFS=$OLD_IFS
 119 fi
 120
 121
 122
 123 verbose_echo "update_url=$update_url"
 124
 125
 126
 127 #if this service isn't enabled then quit
 128 if [ "$enabled" != "1" ]
 129 then
 130         return 0
 131 fi
 132
 133
 134
 135
 136
 137 #compute update interval in seconds
 138 case "$force_unit" in
 139         "days" )
 140                 force_interval_seconds=$(($force_interval*60*60*24))
 141                 ;;
 142         "hours" )
 143                 force_interval_seconds=$(($force_interval*60*60))
 144                 ;;
 145         "minutes" )
 146                 force_interval_seconds=$(($force_interval*60))
 147                 ;;
 148         "seconds" )
 149                 force_interval_seconds=$force_interval
 150                 ;;
 151         * )
 152                 #default is hours
 153                 force_interval_seconds=$(($force_interval*60*60))
 154                 ;;
 155 esac
 156
 157
 158
 159 #compute check interval in seconds
 160 case "$check_unit" in
 161         "days" )
 162                 check_interval_seconds=$(($check_interval*60*60*24))
 163                 ;;
 164         "hours" )
 165                 check_interval_seconds=$(($check_interval*60*60))
 166                 ;;
 167         "minutes" )
 168                 check_interval_seconds=$(($check_interval*60))
 169                 ;;
 170         "seconds" )
 171                 check_interval_seconds=$check_interval
 172                 ;;
 173         * )
 174                 #default is seconds
 175                 check_interval_seconds=$check_interval
 176                 ;;
 177 esac
 178
 179
 180
 181 verbose_echo "force seconds = $force_interval_seconds"
 182 verbose_echo "check seconds = $check_interval_seconds"
 183
 184 #kill old process if it exists & set new pid file
 185 if [ -d /var/run/dynamic_dns ]
 186 then
 187         #if process is already running, stop it
 188         if [ -e "/var/run/dynamic_dns/$service_id.pid" ]
 189         then
 190                 old_pid=$(cat /var/run/dynamic_dns/$service_id.pid)
 191                 test_match=$(ps | grep "^[\t ]*$old_pid")
 192                 verbose_echo "old process id (if it exists) = \"$test_match\""
 193                 if [ -n  "$test_match" ]
 194                 then
 195                         kill $old_pid
 196                 fi
 197         fi
 198
 199 else
 200         #make dir since it doesn't exist
 201         mkdir /var/run/dynamic_dns
 202 fi
 203 echo $$ > /var/run/dynamic_dns/$service_id.pid
 204
 205
 206
 207
 208 #determine when the last update was
 209 current_time=$(date +%s)
 210 last_update=$(( $current_time - (2*$force_interval_seconds) ))
 211 if [ -e "/var/run/dynamic_dns/$service_id.update" ]
 212 then
 213         last_update=$(cat /var/run/dynamic_dns/$service_id.update)
 214 fi
 215 time_since_update=$(($current_time - $last_update))
 216
 217
 218 human_time_since_update=$(( $time_since_update / ( 60 * 60 ) ))
 219 verbose_echo "time_since_update = $human_time_since_update hours"
 220
 221
 222
 223
 224 registered_ip=$(echo $(nslookup "$domain" 2>/dev/null) |  grep -o "Name:.*" | grep -o "$ip_regex")
 225
 226
 227 #do update and then loop endlessly, checking ip every check_interval and forcing an updating once every force_interval
 228
 229 while [ true ]
 230 do
 231         current_ip=$(get_current_ip)
 232
 233
 234         current_time=$(date +%s)
 235         time_since_update=$(($current_time - $last_update))
 236
 237
 238         verbose_echo "Running IP check..."
 239         verbose_echo "current system ip = $current_ip"
 240         verbose_echo "registered domain ip = $registered_ip"
 241
 242
 243         if [ "$current_ip" != "$registered_ip" ]  || [ $force_interval_seconds -lt $time_since_update ]
 244         then
 245                 verbose_echo "update necessary, performing update ..."
 246
 247                 #do replacement
 248                 final_url=$update_url
 249                 for option_var in $ALL_OPTION_VARIABLES
 250                 do
 251                         replace_name=$(echo "\[$option_var\]" | tr 'a-z' 'A-Z')
 252                         replace_value=$(eval echo "\$$option_var")
 253                         final_url=$(echo $final_url | sed s/"$replace_name"/"$replace_value"/g )
 254                 done
 255                 final_url=$(echo $final_url | sed s/"\[IP\]"/"$current_ip"/g )
 256
 257
 258                 verbose_echo "updating with url=\"$final_url\""
 259
 260                 #here we actually connect, and perform the update
 261                 update_output=$( $retrieve_prog "$final_url" )
 262
 263                 verbose_echo "Update Output:"
 264                 verbose_echo "$update_output"
 265                 verbose_echo ""
 266
 267                 #save the time of the update
 268                 current_time=$(date +%s)
 269                 last_update=$current_time
 270                 time_since_update='0'
 271                 registered_ip=$current_ip
 272
 273                 human_time=$(date)
 274                 verbose_echo "update complete, time is: $human_time"
 275
 276                 echo "$last_update" > "/var/run/dynamic_dns/$service_id.update"
 277         else
 278                 human_time=$(date)
 279                 human_time_since_update=$(( $time_since_update / ( 60 * 60 ) ))
 280                 verbose_echo "update unnecessary"
 281                 verbose_echo "time since last update = $human_time_since_update hours"
 282                 verbose_echo "the time is now $human_time"
 283         fi
 284
 285         #sleep for 10 minutes, then re-check ip && time since last update
 286         sleep $check_interval_seconds
 287 done
 288
 289 #should never get here since we're a daemon, but I'll throw it in anyway
 290 return 0
 291
 292
 293
 294