port-forward

#!/usr/bin/env bash

[ $# -eq 0 ] && echo $0 container_name host_port:guest_port[/protocol] && exit 0

HOST_ADDRESS="127.0.0.1"
HOST_PORT=${2%:*}
GUEST_ADDRESS=`podman inspect --format {{.NetworkSettings.Networks.podlab.IPAddress}} "$1"`
GUEST_PORT=${2##*:} GUEST_PORT=${GUEST_PORT%/*}
PROTOCOL=${2##*/} PROTOCOL=${PROTOCOL,,}

print_forward_message() {
    echo "Forwarding with $1 from $2:$3 -> $4"
}

if [ -x "$(command -v socat)" ]; then
    print_forward_message "socat" $HOST_ADDRESS $HOST_PORT $GUEST_PORT
    socat -t -- TCP-LISTEN:$HOST_PORT,reuseaddr,fork EXEC:"podman unshare --rootless-cni socat -t -- STDIN TCP4\:$GUEST_ADDRESS\:$GUEST_PORT"
    exit 0
fi

if [ -x "$(command -v ncat)" ]; then
    print_forward_message "ncat" $HOST_ADDRESS $HOST_PORT $GUEST_PORT
    ncat -k -l $HOST_ADDRESS $HOST_PORT --sh-exec "podman unshare --rootless-cni ncat $GUEST_ADDRESS $GUEST_PORT"
    exit 0
fi

if [ -x "$(command -v netcat)" ]; then
    TMP=`mktemp -d`
    trap "rm -rf $TMP" EXIT
    FIFO="$TMP/`dbus-uuidgen`"
    mkfifo $FIFO
    print_forward_message "netcat (experimental)" $HOST_ADDRESS $HOST_PORT $GUEST_PORT
    nc -kl $HOST_ADDRESS $HOST_PORT < $FIFO | podman unshare --rootless-cni nc $GUEST_ADDRESS $GUEST_PORT > $FIFO
    rm -rf $TMP
    exit 0
fi

echo "You need to install one of ncat, socat or netcat"