Add setup-qbittorent.zsh

setup-qbittorent.zsh

@@ -0,0 +1,60 @@
+#!/usr/bin/env zsh
+
+if [[ "${1}" == '-h' ]] || [[ "${1}" == '--help' ]]; then
+    printf 'usage: %s [-R|-D]\n' "${0}"
+    printf '  -R|-D: remove rules currently in place (default is to add new rules)\n'
+    exit
+fi
+
+setopt pipe_fail
+
+local save_file="${HOME}/.cache/qBittorrent-iptables-save"
+local op='-A'
+if [[ "${1}" == '-D' || "${1}" == '-R' ]]; then
+    if ! [[ -f "${save_file}" ]]; then
+        echo 'No current rules found!'
+        exit 1
+    fi
+    op="-D"
+fi
+local iface="$(ip route | grep '^default' | grep -Po '(?<=dev )[^ ]+')"
+printf 'Using interface: %s\n' "${iface}"
+
+# <-A|-D> <ex_ip> <in_ip>
+function do_rules {
+    emulate -L zsh
+    PS4='Run: '
+    setopt errexit xtrace
+    doas iptables -t filter "${1}" FORWARD -i "${iface}" -o wg0-mullvad -j ACCEPT
+
+    doas iptables -t nat "${1}" PREROUTING -d "${2}"/32 -p tcp -m tcp --dport 62000 \
+         -j DNAT --to-destination "${3}":62000
+    doas iptables -t nat "${1}" PREROUTING -d "${2}"/32 -p udp -m udp --dport 62000 \
+         -j DNAT --to-destination "${3}":62000
+
+    doas iptables -t nat "${1}" POSTROUTING -d "${3}"/32 -p tcp -m tcp --sport 62000 \
+         -j SNAT --to-source "${2}":62000
+    doas iptables -t nat "${1}" POSTROUTING -d "${3}"/32 -p udp -m udp --sport 62000 \
+         -j SNAT --to-source "${2}":62000
+}
+
+if [[ -f "${save_file}" ]]; then
+    local content="$(<"${save_file}")"
+    local lines=("${(@f)content}")
+    printf 'Old rules found for\nex_ip: %s\nin_ip: %s\n' "${lines[1]}" "${lines[2]}"
+    printf 'Removing...\n'
+    do_rules -D "${lines[1]}" "${lines[2]}"
+    rm -f "${save_file}"
+    printf 'Done!\n'
+    [[ "${op}" == '-D' ]] && exit
+fi
+
+local ex_ip in_ip
+ex_ip="$(curl -4 icanhazip.com)" || { echo 'Could not fetch ip!'; exit 1 }
+in_ip="$(ip addr show dev wg0-mullvad | \
+         awk '/^ *inet [0-9]+/ { print substr($2,0,index($2,"/") - 1) }')" ||
+    { echo 'Could not find wireguard iterface address!'; exit 1 }
+printf 'Adding rules for:\nex_ip: %s\nin_ip: %s\n' "${ex_ip}" "${in_ip}"
+printf '%s\n%s\n' "${ex_ip}" "${in_ip}" >"${save_file}"
+
+do_rules -A "${ex_ip}" "${in_ip}"