#!/bin/bash
# /etc/hosts and /root/.ssh/config must be edited for this to work:
# TARGET is the computer to which you are tunneling
# put an alias $HOSTHAME-tunnel on the same /etc/hosts line as $TARGET
# example:
# 10.10.0.100 myserver.my mylaptop-tunnel
# 
# under Host $HOSTNAME-tunnel in /root/.ssh/config
# optionally change Port, User, and/or IdentityFile
# example:
# Host mylaptop-tunnel
# IdentityFile /home/somebody/.ssh/id_dsa_special
# User somebody
# Port 9876
#
# no need to set -o StrictHostKeyChecking=no with scp when using this method
# but test the script before putting in cron, to cache the host key
DEBUGGING=1  # set to 0 for less verbose output
if ! scp -q /etc/profile $HOSTNAME-tunnel:/tmp/; then
 exec 3< <(lsof -n -P -itcp -R)
 while read -u 3 command pid ppid ignored; do
  if [ "$DEBUGGING" ]; then
   echo FOUND: $command $pid $ppid >&2
  fi
  if [ "$command" = "ssh" -a "$ppid" = 1 ]; then
   if [ "$DEBUGGING" ]; then
    echo Killing tunnel process $pid >&2
   fi
   kill $pid
  fi
 done
fi