Backup Script

1. You want to schedule a backup done via a cron job.
2. You want the script initiated from, and stored in a safe location
   on a server on the network, (not on the router).
3. You do not wish to install SFTP just for these backups.

The script at the bottom of this page will create and download the backup without needing to have SFTP enabled on the router.

We could, of course, create the backup as a cron job on the router itself, and then use the mechanism applied in the script below to download the backup file. However, let's assume you want everything done in just one run of the script. To achieve this, the script covers creation of the backup in an individual file with timestamp and download.

In this way, just one run of the script on the backup server will create the backup and download it to to a safe location.

Action is based on using a here doc to execute commands on the router.

The backup is created using the “nvram save” command. This is how backups are done “under the hood” in the web interface.

You may cross-check that the backups are identical to the ones via the GUI using the following steps:

1. Download the backup via the graphical interface
2. Create a backup via a script
3. Copy both files to router
4. Convert both files via the command “nvram convert <filename1/2> > result_file1/2.txt”
5. Perform a diff between the two resulting text files.

The script then archives the resulting data in a tar file and sends it through the netcat command, transferring it over the network.

A configurable number of backups is kept. Older ones are deleted.

1. The netcat command must be available on the backup server.
2. The router's root user must have access to the public SSH key of the user executing the script on backup server.

 #!/bin/bash
 
 USER=root
 LOCAL_ID_FILE=/home/${LOGNAME}/.ssh/id_tomato_ecdsa
 PORT=5555
 BACKUP_DIR=/home/${LOGNAME}/Router_Backups
 SCRIPT_FILE=nvram_save_cfg.sh
 PREFIX=FreshTomato
 EXT=.cfg
 TRANSFER_FILENAME=config.tar
 
 NO_OF_DIFF_FILES_TO_BE_KEPT=10
 
 ROUTER=`ip r | grep default | head -1 | cut -d " " -f 3`
 pushd ${BACKUP_DIR}
 
 (netcat -l -p ${PORT} > ${TRANSFER_FILENAME}) &
 #
 # Thinks like
 # VAR=`nvram get os_version`
 # seem not to work in bash via here doc, so write results into script file and source it
 # Further, the individual filename is generally not known, so tar it into temp file
 #
 ssh ${USER}@${ROUTER} -i ${LOCAL_ID_FILE}<<ENDSSH
         rm -f ${SCRIPT_FILE} ${TRANSFER_FILENAME} ${PREFIX}_*_20[234][0-9][01][0-9][0123][0-9]_[012][0-9][0-5][0-9]${EXT}
         echo "nvram save ${PREFIX}" >> ${SCRIPT_FILE}
         nvram get os_version | sed -e "s/ .*$//" >> ${SCRIPT_FILE}
         echo "on" >> ${SCRIPT_FILE}
         nvram get t_model_name | tr " " "_" >> ${SCRIPT_FILE}
         nvram get router_name >> ${SCRIPT_FILE}
         date +%Y%m%d_%H%M >> ${SCRIPT_FILE}
         sed -e "N;N;N;N;N;s/\n/_/g;s/$/${EXT}/" -i ${SCRIPT_FILE}
         cat ${SCRIPT_FILE}
         source ${SCRIPT_FILE}
         tar -cvf ${TRANSFER_FILENAME} *_20[234][0-9][01][0-9][0123][0-9]_[012][0-9][0-5][0-9]${EXT}
         cat ${TRANSFER_FILENAME} | nc caisfiles ${PORT}
         sleep 3 # just wait a little bit before deleting the files not needed here any more
         rm -f ${SCRIPT_FILE} ${TRANSFER_FILENAME} ${PREFIX}_*_20[234][0-9][01][0-9][0123][0-9]_[012][0-9][0-5][0-9]${EXT}
 ENDSSH
 
 tar -xvf ${TRANSFER_FILENAME}
 rm ${TRANSFER_FILENAME}
 echo deleting:
 rm -fv `ls -t ${PREFIX}_*_20[234][0-9][01][0-9][0123][0-9]_[012][0-9][0-5][0-9]${EXT} | sed -e 1,${NO_OF_DIFF_FILES_TO_BE_KEPT}d`
 popd