#!/bin/sh  /etc/rc.common
#
# Copyright (c) 2014, 2019-2020 The Linux Foundation. All rights reserved.
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

# The shebang above has an extra space intentially to avoid having
# openwrt build scripts automatically enable this package starting
# at boot.

START=26

sysctl_update() {
  local name value file
  name=${1//\//\\/}
  value=${2//\//\\/}
  file=${3:-/etc/sysctl.d/qca-nss-ecm.conf}
  sed -i -e '/^#\?\(\s*'"${name}"'\s*=\s*\).*/{s//\1'"${value}"'/;:a;n;ba;q}' \
    -e '$a'"${name}"'='"${value}" "${file}"
  sysctl -w ${name}=${value}
}

get_front_end_mode() {
  config_load "ecm"
  config_get front_end global acceleration_engine "auto"

  case $front_end in
    auto)
      echo '0'
      ;;
    nss)
      echo '1'
      ;;
    *)
      echo 'uci_option_acceleration_engine is invalid'
  esac
}

enable_bridge_filtering() {
  sysctl_update net.bridge.bridge-nf-call-arptables 1
  sysctl_update net.bridge.bridge-nf-call-iptables 1
  sysctl_update net.bridge.bridge-nf-call-ip6tables 1
}

disable_bridge_filtering() {
  sysctl_update net.bridge.bridge-nf-call-arptables 0
  sysctl_update net.bridge.bridge-nf-call-iptables 0
  sysctl_update net.bridge.bridge-nf-call-ip6tables 0
}

load_ecm() {
  [ -d /sys/module/ecm ] || {
    insmod ecm front_end_selection="$(get_front_end_mode)"
    echo 1 > /sys/kernel/debug/ecm/ecm_classifier_default/accel_delay_pkts
  }

  # Set conntrack event mode to 1 for 6.1 kernel to get the conntrack events from ECM
  local kernel_major
  kernel_major=$(uname -r |cut -d. -f1)
  if [ "$kernel_major" -eq 6 ]; then
    echo 1 > /proc/sys/net/netfilter/nf_conntrack_events
  fi
}

unload_ecm() {
  disable_bridge_filtering

  # Change it back to 6.1 linux's default setting
  local kernel_major
  kernel_major="$(uname -r |cut -d. -f1)"
  if [ "$kernel_major" -eq 6 ]; then
    echo 2 > /proc/sys/net/netfilter/nf_conntrack_events
  fi

  if [ -d /sys/module/ecm ]; then
    #
    # Stop ECM frontends
    #
    echo 1 > /sys/kernel/debug/ecm/front_end_ipv4_stop
    echo 1 > /sys/kernel/debug/ecm/front_end_ipv6_stop

    #
    # Defunct the connections
    #
    echo 1 > /sys/kernel/debug/ecm/ecm_db/defunct_all
    sleep 5

    rmmod ecm
    sleep 1
  fi
}

start() {
  load_ecm

  # If the acceleration engine is NSS, enable wifi redirect
  [ -d /sys/kernel/debug/ecm/ecm_nss_ipv4 ] && sysctl -w dev.nss.general.redirect=1

  # If bridge filtering is enabled, apply and persist the sysctl flags
  local bridge_filtering_enabled
  bridge_filtering_enabled="$(uci get ecm.@general[0].enable_bridge_filtering)"
  if [ "$bridge_filtering_enabled" -eq 1 ]; then
    echo "Bridge filtering is enabled in the ECM config, this will cause issues with NAT loopback!"
    enable_bridge_filtering
  else
    disable_bridge_filtering
  fi

  if [ -d /sys/module/qca_ovsmgr ]; then
    insmod ecm_ovs
  fi
}

stop() {
  # If ECM is already not loaded, just return
  if [ ! -d /sys/module/ecm ]; then
    return
  fi

  # If the acceleration engine is NSS, disable wifi redirect
  [ -d /sys/kernel/debug/ecm/ecm_nss_ipv4 ] && sysctl -w dev.nss.general.redirect=0

  if [ -d /sys/module/ecm_ovs ]; then
    rmmod ecm_ovs
  fi

  unload_ecm
}