ssh port_forwarding functions

port_forwarding.sh

# read in zsh is different from bash
# https://superuser.com/questions/555874/zsh-read-command-fails-within-bash-function-read1-p-no-coprocess
# in bash, read -p "prompt" var
# but in zsh, read "var?prompt"
function port_forwarding_local() {
  echo "port forwarding to remote server"

  read "local_host?local_host (default is empty): "
  read "local_port?local_port: "
  if [[ -z "${local_port}" ]]; then
    echo "local_port cannot be empty"
    return 1
  fi
  if [[ -n "${local_host}" ]]; then
    local_addr="${local_host}:${local_port}"
  else
    local_addr="${local_port}"
  fi

  read "remote_host?remote_host: "
  if [[ -z "${remote_host}" ]]; then
    echo "remote_host cannot be empty"
    return 1
  fi

  read "remote_port?remote_port: "
  if [[ -z "${remote_port}" ]]; then
    echo "remote_port cannot be empty"
    return 1
  fi

  remote_addr="${remote_host}:${remote_port}"

  read "remote_server?remote_server: "
  if [[ -z "${remote_server}" ]]; then
    echo "remote_server cannot be empty"
    return 1
  fi

  local cmd="ssh -L ${local_addr}:${remote_addr} -N -C ${remote_server}"
  echo ${cmd}
  bash -c "${cmd}"
}

function port_forwarding_remote() {
  echo "port forwarding to localhost"

  read "remote_host?remote_host (default is empty): "
  read "remote_port?remote_port: "
  if [[ -z "${remote_port}" ]]; then
    echo "remote_port cannot be empty"
    return 1
  fi
  if [[ -n "${remote_host}" ]]; then
    remote_addr="${remote_host}:${remote_port}"
  else
    remote_addr="${remote_port}"
  fi

  read "local_host?local_host (default is 127.0.0.1): "
  if [[ -z "${local_host}" ]]; then
    local_host="127.0.0.1"
  fi
  read "local_port?local_port: "
  if [[ -z "${local_port}" ]]; then
    echo "local_port cannot be empty"
    return 1
  fi
  local_addr="${local_host}:${local_port}"

  read "remote_server?remote_server: "
  if [[ -z "${remote_server}" ]]; then
    echo "remote_server cannot be empty"
    return 1
  fi

  local cmd="ssh -R ${remote_addr}:${local_addr} -N -C ${remote_server}"
  echo ${cmd}
  bash -c "${cmd}"
}

function port_forwarding_dynamic() {
  echo "port forwarding as dynamic socks5 proxy"

  read "local_port?local_port: "
  if [[ -z "${local_port}" ]]; then
    echo "local_port cannot be empty"
    return 1
  fi

  read "remote_server?remote_server: "
  if [[ -z "${remote_server}" ]]; then
    echo "remote_server cannot be empty"
    return 1
  fi

  local cmd="ssh -D ${local_port} -N -C ${remote_server}"
  echo ${cmd}
  bash -c "${cmd}"
}