1 files changed, 98 insertions, 0 deletions
diff --git a/src/system/on-dhcp-event.sh b/src/system/on-dhcp-event.sh
new file mode 100755
index 000000000..d671bffd6
--- /dev/null
+++ b/src/system/on-dhcp-event.sh
@@ -0,0 +1,98 @@
+#!/bin/bash
+
+# This script came from ubnt.com forum user "bradd" in the following post
+# http://community.ubnt.com/t5/EdgeMAX/Automatic-DNS-resolution-of-DHCP-client-names/td-p/651311
+# It has been modified by Ubiquiti to update the /etc/host file
+# instead of adding to the CLI.
+# Thanks to forum user "itsmarcos" for bug fix & improvements
+# Thanks to forum user "ruudboon" for multiple domain fix
+# Thanks to forum user "chibby85" for expire patch and static-mapping
+
+if [ $# -lt 5 ]; then
+  echo Invalid args
+  logger -s -t on-dhcp-event "Invalid args \"$@\""
+  exit 1
+fi
+
+action=$1
+client_name=$2
+client_ip=$3
+client_mac=$4
+domain=$5
+file=/etc/hosts
+changes=0
+
+if [ "$domain" == "..YYZ!" ]; then
+    client_fqdn_name=$client_name
+    client_search_expr=$client_name
+else
+    client_fqdn_name=$client_name.$domain
+    client_search_expr="$client_name\\.$domain"
+fi
+
+case "$action" in
+  commit) # add mapping for new lease
+    echo "- new lease event, setting static mapping for host "\
+         "$client_fqdn_name (MAC=$client_mac, IP=$client_ip)"
+    #
+    # grep fails miserably with \t in the search expression.
+    # In the following line one <Ctrl-V> <TAB> is used after $client_search_expr
+    # followed by a single space
+    grep -q " $client_search_expr	 #on-dhcp-event " $file
+    if [ $? == 0 ]; then
+       echo pattern found, removing
+       wc1=`cat $file | wc -l`
+       sudo sed -i "/ $client_search_expr\t #on-dhcp-event /d" $file
+       wc2=`cat $file | wc -l`
+       if [ "$wc1" -eq "$wc2" ]; then
+         echo No change
+       fi
+    else
+       echo pattern NOT found
+    fi
+
+    # check if hostname already exists (e.g. a static host mapping)
+    # if so don't overwrite
+    grep -q " $client_search_expr	 " $file
+    if [ $? == 0 ]; then
+       echo host $client_fqdn_name already exists, exiting
+       exit 1
+    fi
+
+    line="$client_ip\t $client_fqdn_name\t #on-dhcp-event $client_mac"
+    sudo sh -c "echo -e '$line' >> $file"
+    ((changes++))
+    echo Entry was added
+    ;;
+
+  release) # delete mapping for released address
+    echo "- lease release event, deleting static mapping for host $client_fqdn_name"
+    wc1=`cat $file | wc -l`
+    sudo sed -i "/ $client_search_expr\t #on-dhcp-event /d" $file
+    wc2=`cat $file | wc -l`
+    if [ "$wc1" -eq "$wc2" ]; then
+      echo No change
+    else
+      echo Entry was removed
+      ((changes++))
+    fi
+    ;;
+
+  *)
+    logger -s -t on-dhcp-event "Invalid command \"$1\""
+    exit 1;
+    ;;
+esac
+
+if [ $changes -gt 0 ]; then
+  echo Success
+  pid=`pgrep pdns_recursor`
+  if [ -n "$pid" ]; then
+     sudo rec_control reload-zones
+  fi
+else
+  echo No changes made
+fi
+exit 0
+
+