#!/bin/bash /usr/lib/turtle/turtle_module
VERSION="1.0"
DESCRIPTION="Proxies TCP over Ping (ICMP) traffic"
CONF=/tmp/ptunnel.form

: ${DIALOG_OK=0}
: ${DIALOG_CANCEL=1}
: ${DIALOG_HELP=2}
: ${DIALOG_EXTRA=3}
: ${DIALOG_ITEM_HELP=4}
: ${DIALOG_ESC=255}

function start {
  if [ -s /etc/config/ptunnel ]
  then
    ptunnel_host=$(uci get ptunnel.host)
    ptunnel_local_port=$(uci get ptunnel.lport)
    ptunnel_dst_host=$(uci get ptunnel.rhost)
    ptunnel_dst_port=$(uci get ptunnel.rport)
    echo ptunnel -p "$ptunnel_host" -lp "$ptunnel_local_port" -da "$ptunnel_dst_host" -dp "$ptunnel_dst_port" > /dev/null &
    ptunnel -p "$ptunnel_host" -lp "$ptunnel_local_port" -da "$ptunnel_dst_host" -dp "$ptunnel_dst_port" > /dev/null &
    echo -n "ptunnel started with pid: "; pidof ptunnel
  else
    touch /etc/config/ptunnel
    echo "ptunnel not configured"
  fi
}

function stop {
  killall ptunnel
}

function status {
  if pgrep ptunnel > /dev/null; then echo "1"; else echo "0"; fi
}

function configure {

  if [ -s /etc/config/ptunnel ]
  then
    ptunnel_host=$(uci get ptunnel.host)
    ptunnel_local_port=$(uci get ptunnel.lport)
    ptunnel_dst_host=$(uci get ptunnel.rhost)
    ptunnel_dst_port=$(uci get ptunnel.rport)
  else
    touch /etc/config/ptunnel
  fi

  dialog --ok-label "Submit" \
    --help-button \
    --title "PTunnel Configuration" \
    --form "\nPTunnel Server: Address of the server running the ptunnel proxy.\n\
Local Port: Port on localhost from which traffic will be tunneled.\n\
Dst Server: Destination host to which traffic will be proxied.\n\
Dst Port: Destination port to which traffic will be proxied.\n\n" 16 75 4\
    "PTunnel Host:"	1 1	"$ptunnel_host"		1 15 40 0 \
    "Local Port:"	2 1	"$ptunnel_local_port"	2 15 40 0 \
    "Dst. Host:"	3 1	"$ptunnel_dst_host"	3 15 40 0 \
    "Dst. Port:"	4 1	"$ptunnel_dst_port"	4 15 40 0 \
  2>$CONF

  return=$?

  case $return in
    $DIALOG_OK)
      cat $CONF | { 
        read -r ptunnel_host
        read -r ptunnel_local_port
        read -r ptunnel_dst_host
        read -r ptunnel_dst_port
        touch /etc/config/ptunnel
        uci set ptunnel.host="$ptunnel_host"
        uci set ptunnel.lport="$ptunnel_local_port"
        uci set ptunnel.rhost="$ptunnel_dst_host"
        uci set ptunnel.rport="$ptunnel_dst_port"
        uci commit ptunnel
        rm $CONF
        clear
      };;
    $DIALOG_CANCEL)
      rm $CONF
      clear
      exit;;
    $DIALOG_HELP)
      dialog --title "Help" \
        --msgbox "Ping Tunnel, or ptunnel, is an application that allows you to reliably tunnel TCP connections to a remote host using ICMP echo request and reply packets, commonly known as ping requests and replies.\
A common use case is to provide a secure covert reverse shell via SSH.\n\n\
Ping Tunnel configuration accepts the following:\n\n\
* Ptunnel Host: Address of the server running the ptunnel proxy - often a VPS or other such machine online with a static IP or domain.\n\
* Local Port: TCP listening port on localhost through which traffic will be proxied to the ptunnel host.\n\
* Dst Server: Destination host of the remote proxy to which traffic will be forwarded.\n\
* Dst Port: Destination port to remote proxy to which traffic will be forwarded.\n\n\
Example: example.com, 8000, example.com, 22\n\n\
This would configure ptunnel to connect to the ptunnel server running on domain.com and forward all traffic going to port 8000 on localhost to port 22 on example.com.\n\n\
With this an autoSSH session to the SSH server running on example.com port 22 may be established through the Ping Tunnel via localhost port 8000.\
" 20 60
      configure
      ;;
    $DIALOG_ESC)
      clear;;
  esac
}