ddwrt-wol-port-forward.sh

#!/bin/sh
DEBUG= # uncomment/comment to enable/disable debug mode

#          name: ddwrt-wol-port-forward.sh
#       version: 1.2.0, 07-jan-2022, by eibgrad
#       purpose: port forward w/ wol activation
#   script type: wanup (autostart) + startup (autostart)
#  installation:
#    1. enable jffs2 (administration->jffs2)
#    2. enable syslogd (services->services->system log)
#    3. use shell (telnet/ssh) to execute one of the following commands:
#         curl -kLs bit.ly/ddwrt-installer|tr -d '\r'|sh -s -- --dir /tmp NUb73JqK
#       or
#         wget -qO - bit.ly/ddwrt-installer|tr -d '\r'|sh -s -- --dir /tmp NUb73JqK
#    4. use vi editor to modify installer options:
#         vi /tmp/ddwrt-wol-port-forward.sh
#    5. execute installer:
#         /tmp/ddwrt-wol-port-forward.sh
#    6. reboot

SCRIPTS_DIR='/jffs/etc/config'; mkdir -p $SCRIPTS_DIR

SCRIPT1="$SCRIPTS_DIR/ddwrt-wol-pf.wanup"
SCRIPT2="$SCRIPTS_DIR/ddwrt-wol-pf.startup"

# ------------------------- begin ddwrt-wol-pf.wanup ------------------------- #
cat << 'EOF' > $SCRIPT1
#!/bin/sh
set -x # uncomment/comment to enable/disable debug mode
{
#!/bin/sh

# ------------------------------ BEGIN OPTIONS ------------------------------- #

# protocol (tcp|udp) of port forward
PROTO='tcp'

# source ip(s)/network(s) of port forward (comma-separated)
SOURCE='0.0.0.0/0'

# external port of port forward
EXT_PORT='5900'

# internal ip of port forward
INT_IP='192.168.1.100'

# internal port of port forward
INT_PORT='5900'

# ------------------------------- END OPTIONS -------------------------------- #

# ---------------------- DO NOT CHANGE BELOW THIS LINE ----------------------- #

# create port forward
iptables -t nat -I PREROUTING -p $PROTO -s $SOURCE -d $(nvram get wan_ipaddr) \
    --dport $EXT_PORT -j DNAT --to $INT_IP:$INT_PORT
iptables -I FORWARD -p $PROTO -s $SOURCE -d $INT_IP --dport $INT_PORT -j ACCEPT

# record access of port forward to log
iptables -I FORWARD -p $PROTO -s $SOURCE -d $INT_IP --dport $INT_PORT \
    -m state --state NEW -j LOG --log-prefix "WOL Port Forward "

} 2>&1 | logger -t $(basename $0)[$$]
EOF
[ ${DEBUG+x} ] || sed -ri 's/^(set -x)/#\1/g' $SCRIPT1
chmod +x $SCRIPT1
echo "installed: $SCRIPT1"
# -------------------------- end ddwrt-wol-pf.wanup -------------------------- #

# ------------------------ begin ddwrt-wol-pf.startup ------------------------ #
cat << 'EOF' > $SCRIPT2
#!/bin/sh
set -x # uncomment/comment to enable/disable debug mode
(
# ------------------------------ BEGIN OPTIONS ------------------------------- #

# mac address of internal ip (unspecified = static lease search)
MAC_ADDR='' # hexidecimal format: XX:XX:XX:XX:XX:XX

# broadcast interface of internal ip
BCAST_IF='br0'

# how often (in secs) to check for new kernel messages
INTERVAL=10

# ------------------------------- END OPTIONS -------------------------------- #

# ---------------------- DO NOT CHANGE BELOW THIS LINE ----------------------- #

get_val() { sed -rn "s/^$1=(.*)/\1/p" $SCRIPT1 | tr -d \'\"; }

get_mac() {
  sed -rn \
    "s/^dhcp-host=.*(([[:xdigit:]]{2}:){5}[[:xdigit:]]{2}).*,$1(,.*|$)/\1/p" \
      /tmp/dnsmasq.conf | head -n1
}

# internal ip of port forward
INT_IP=$(get_val 'INT_IP')

# protocol (tcp|udp) of port forward
PROTO=$(get_val 'PROTO' | awk '{print toupper($0)}')

# internal port of port forward
INT_PORT=$(get_val 'INT_PORT')

# broadcast ip of internal ip's network interface
BCAST_IP="$(ifconfig $BCAST_IF | awk '/Bcast/{split ($3,A,":"); print A[2]}')"

# mask used for finding wol messages
WOL_MSG_MASK="^WOL Port Forward .* DST=$INT_IP .* PROTO=$PROTO .* DPT=$INT_PORT "

# work files
CURR_MSG="/tmp/tmp.$$.curr_msg"
PREV_MSG="/tmp/tmp.$$.prev_msg"; > $PREV_MSG

# wait for *reliable* internet connection
until ping -qc1 -W3 8.8.8.8 &>/dev/null; do sleep 10; done

# validate mac address
if [ ! "$MAC_ADDR" ]; then
    MAC_ADDR=$(get_mac $INT_IP)
    if [ ! "$MAC_ADDR" ]; then
        echo "fatal error: mac address not found: $INT_IP"
        exit 1
    fi
else
    if ! echo "$MAC_ADDR" | \
            grep -qE '^([[:xdigit:]]{2}:){5}[[:xdigit:]]{2}$'; then
        echo "fatal error: invalid/malformed mac address: $MAC_ADDR"
        exit 1
    fi
fi

while sleep $INTERVAL; do
    # extract all wol messages
    dmesg | grep "$WOL_MSG_MASK" > $CURR_MSG

    # if there are any new wol messages, then wol as necessary
    if [ -s $CURR_MSG ] && ! ping -qc1 -W3 $INT_IP &>/dev/null; then
        if [ ! -s $PREV_MSG ] || \
                grep -m1 -Fxvf $PREV_MSG $CURR_MSG >/dev/null; then

            # try up to three (3) times to wake the device
            for i in 1 2 3; do
                echo "info: waking up $MAC_ADDR (attempt #${i}) ..."
                /usr/sbin/wol -i $BCAST_IP $MAC_ADDR >/dev/null && sleep 20 || break
                if ping -qc1 -W3 $INT_IP &>/dev/null; then
                    echo "info: $MAC_ADDR is alive!"
                    break
                fi
                [ $i -eq 3 ] && echo "warning: $MAC_ADDR did NOT respond :("
            done
        fi
    fi

    # remember which wol messages have already been processed
    mv $CURR_MSG $PREV_MSG
done
) 2>&1 | logger -t $(basename $0)[$$] &
EOF
[ ${DEBUG+x} ] || sed -ri 's/^(set -x)/#\1/g' $SCRIPT2
sed -i "s:\$SCRIPT1:$SCRIPT1:g" $SCRIPT2
chmod +x $SCRIPT2
echo "installed: $SCRIPT2"
# ------------------------- end ddwrt-wol-pf.startup ------------------------- #