ssh-persist

#!/bin/bash
usage()
{
cat << EOF
usage: $0 options

This sets up a persistent reverse tunnel (shell) to another machine

OPTIONS:
   -h      Show this message
   -r      'remote' machine (default localhost)
   -p      Port on remote (this) machine to be forwarded (default 22/ssh)
   -l      'local' machine (the one you want to connect to here, from)
   -q      Port on local (foreign) machine to be tunneled to the remote port (default 2222)
   -u      Use an alternative user on 'local'
   -v      Verbose
EOF
}

while getopts “hr:p:l:q:u:v” OPTION
do
     case $OPTION in
         h)
             usage
             exit 1
             ;;
         r)
             REMOTE=$OPTARG
             ;;
         p)
             REMOTE_PORT=$OPTARG
             ;;
         l)
             LOCAL=$OPTARG
             ;;
         q)
             LOCAL_PORT=$OPTARG
             ;;
         u)
             USER= $OPTARG
             ;;
         v)
             VERBOSE=" -v "
             ;;
         ?)
             usage
             exit
             ;;
     esac
done

#Set Defaults
[[ -n $REMOTE ]] && REMOTE= $REMOTE || REMOTE="localhost"
[[ -n $REMOTE_PORT ]] && REMOTE_PORT=$REMOTE_PORT || REMOTE_PORT="22"
[[ -n $LOCAL_PORT ]] && LOCAL_PORT=$LOCAL_PORT || LOCAL_PORT="2222"
[[ -n $USER ]] && USER=$USER || USER=`whoami`

trap "logger Tunnel to $LOCAL died permenantly; exit" SIGINT SIGTERM EXIT

while true;do
    ssh $VERBOSE -NR $LOCAL_PORT:localhost:$REMOTE_PORT $LOCAL
    logger "Tunnel to $LOCAL died (hopefully) temporarily, sleeping for 10 seconds, then trying again"
    sleep 10
done;

logger "Someone is trying to kill tunnel to $LOCAL!"