#!/bin/bash

# config.sh sets up defaults for CAKE-autorate

# config.sh is a part of CAKE-autorate
# CAKE-autorate automatically adjusts bandwidth for CAKE in dependence on detected load and RTT

# Author: @Lynx (OpenWrt forum)
# Inspiration taken from: @moeller0 (OpenWrt forum)
# Modified by Ycarus (Yannick Chabanois) for OpenMPTCProuter:
#  * Get configuration via uci

INTERFACE=$1

# *** OUTPUT OPTIONS ***

#output_processing_stats=1 # enable (1) or disable (0) output monitoring lines showing processing stats
output_processing_stats=$(uci -q get sqm.${INTERFACE}.output_processing_stats || echo "0")
#output_cake_changes=0     # enable (1) or disable (0) output monitoring lines showing cake bandwidth changes
output_cake_changes=$(uci -q get sqm.${INTERFACE}.output_cake_changes || echo "0")
#debug=0			  # enable (1) or disable (0) out of debug lines
debug=$(uci -q get sqm.common.debug || echo "0")

# *** STANDARD CONFIGURATION OPTIONS ***

#dl_if=ifb4eth1 # download interface
#dl_if=$(uci -q get sqm.${INTERFACE}.download_interface)
dl_if=ifb4$(uci -q get sqm.${INTERFACE}.interface)
#ul_if=eth1        # upload interface
#ul_if=$(uci -q get sqm.${INTERFACE}.upload_interface)
ul_if=$(uci -q get sqm.${INTERFACE}.interface)

#reflector_ping_interval_s=0.2 # (seconds, e.g. 0.2s or 2s)
reflector_ping_interval_s=$(uci -q get sqm.${INTERFACE}.reflector_ping_interval_s || echo "0.2")

# list of reflectors to use and number of pingers to initiate
# pingers will be initiated with reflectors in the order specified in the list 
# additional reflectors will be used to replace any reflectors that go stale
# so e.g. if 6 reflectors are specified and the number of pingers is set to 4, the first 4 reflectors will be used initially
# and the remaining 2 reflectors in the list will be used in the event any of the first 4 go bad
# a bad reflector will go to the back of the queue on reflector rotation
reflectors=("1.1.1.1" "1.0.0.1" "8.8.8.8" "8.8.4.4" "9.9.9.9" "9.9.9.10")
no_pingers=$(uci -q get sqm.${INTERFACE}.no_pingers || echo "4")

# delay threshold in ms is the extent of RTT increase to classify as a delay
# this is automatically adjusted based on maximum on the wire packet size
# (adjustment significant at sub 12Mbit/s rates, else negligible)  
#delay_thr_ms=25 # (milliseconds)
delay_thr_ms=$(uci -q get sqm.${INTERFACE}.delay_thr_ms || echo "25")

#min_dl_shaper_rate_kbps=10000  # minimum bandwidth for download (Kbit/s)
min_dl_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.min_download)
#base_dl_shaper_rate_kbps=100000 # steady state bandwidth for download (Kbit/s)
base_dl_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.download)
#max_dl_shaper_rate_kbps=200000  # maximum bandwidth for download (Kbit/s)
max_dl_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.max_download)

#min_ul_shaper_rate_kbps=10000  # minimum bandwidth for upload (Kbit/s)
min_ul_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.min_upload)
#base_ul_shaper_rate_kbps=100000 # steady state bandwidth for upload (KBit/s)
base_ul_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.upload)
#max_ul_shaper_rate_kbps=200000  # maximum bandwidth for upload (Kbit/s)
max_ul_shaper_rate_kbps=$(uci -q get sqm.${INTERFACE}.max_upload)

# sleep functionality saves unecessary pings and CPU cycles by
# pausing all active pingers when connection is not in active use
#enable_sleep_function=1 # enable (1) or disable (0) sleep functonality 
enable_sleep_function=$(uci -q get sqm.${INTERFACE}.enable_sleep_functions || echo "1")
#connection_active_thr_kbps=500 # threshold in Kbit/s below which dl/ul is considered idle
connection_active_thr_kbps=$(uci -q get sqm.${INTERFACE}.connection_active_thr_kbps || echo "500")
#sustained_idle_sleep_thr_s=60  # time threshold to put pingers to sleep on sustained dl/ul achieved rate < idle_thr (seconds)
sustained_idle_sleep_thr_s=$(uci -q get sqm.${INTERFACE}.substained_idle_sleep_thr_s || echo "60")

#startup_wait_s=0 # number of seconds to wait on startup (e.g. to wait for things to settle on router reboot)
startup_wait_s=$(uci -q get sqm.${INTERFACE}.startup_wait_s || echo "60")

# *** ADVANCED CONFIGURATION OPTIONS ***

# interval in ms for monitoring achieved rx/tx rates
# this is automatically adjusted based on maximum on the wire packet size
# (adjustment significant at sub 12Mbit/s rates, else negligible)  
monitor_achieved_rates_interval_ms=100 # (milliseconds) 

# bufferbloat is detected when (bufferbloat_detection_thr) samples
# out of the last (bufferbloat detection window) samples are delayed
bufferbloat_detection_window=4  # number of samples to retain in detection window
bufferbloat_detection_thr=2     # number of delayed samples for bufferbloat detection

# RTT baseline against which to measure delays
# the idea is that the baseline is allowed to increase slowly to allow for path changes
# and slowly enough such that bufferbloat will be corrected well before the baseline increases,
# but it will decrease very rapidly to ensure delays are measured against the shortest path
alpha_baseline_increase=0.001 # how rapidly baseline RTT is allowed to increase
alpha_baseline_decrease=0.9   # how rapidly baseline RTT is allowed to decrease

# rate adjustment parameters 
# bufferbloat adjustment works with the lower of the adjusted achieved rate and adjusted shaper rate
# to exploit that transfer rates during bufferbloat provide an indication of line capacity
# otherwise shaper rate is adjusted up on load high, and down on load idle or low
# and held the same on load medium
achieved_rate_adjust_bufferbloat=0.9 # how rapidly to reduce achieved rate upon detection of bufferbloat 
shaper_rate_adjust_bufferbloat=0.9   # how rapidly to reduce shaper rate upon detection of bufferbloat 
shaper_rate_adjust_load_high=1.01    # how rapidly to increase shaper rate upon high load detected 
shaper_rate_adjust_load_low=0.98     # how rapidly to return to base shaper rate upon idle or low load detected 

# the load is categoried as low if < medium_load_thr, medium if > medium_load_thr and high if > high_load_thr relative to the current shaper rate
medium_load_thr=0.25 # % of currently set bandwidth for detecting medium load
high_load_thr=0.75   # % of currently set bandwidth for detecting high load

# refractory periods between successive bufferbloat/decay rate changes
bufferbloat_refractory_period_ms=300 # (milliseconds)
decay_refractory_period_ms=1000 # (milliseconds)

# interval for checking reflector health
reflector_health_check_interval_s=1 # (seconds)
# deadline for reflector response not to be classified as an offence against reflector
reflector_response_deadline_s=1 # (seconds)

# reflector misbehaving is detected when $reflector_misbehaving_detection_thr samples
# out of the last (reflector misbehaving detection window) samples are offences
# thus with a 1s interval, window 60 and detection_thr 3, this is tantamount to
# 3 offences within the last 60s 
reflector_misbehaving_detection_window=60
reflector_misbehaving_detection_thr=3

global_ping_response_timeout_s=10 # timeout to set shaper rates to min on no ping response whatsoever (seconds)

if_up_check_interval_s=10 # time to wait before re-checking if rx/tx bytes files exist (e.g. from boot state)

# verify these are correct using 'cat /sys/class/...'
case "${dl_if}" in
    \veth*)
        rx_bytes_path="/sys/class/net/${dl_if}/statistics/tx_bytes"
        ;;
    \ifb*)
        rx_bytes_path="/sys/class/net/${dl_if}/statistics/tx_bytes"
        ;;
    *)
        rx_bytes_path="/sys/class/net/${dl_if}/statistics/rx_bytes"
        ;;
esac

case "${ul_if}" in
    \veth*)
        tx_bytes_path="/sys/class/net/${ul_if}/statistics/rx_bytes"
        ;;
    \ifb*)
        tx_bytes_path="/sys/class/net/${ul_if}/statistics/rx_bytes"
        ;;
    *)
        tx_bytes_path="/sys/class/net/${ul_if}/statistics/tx_bytes"
        ;;
esac

if (( $debug )) ; then
    echo "DEBUG: rx_bytes_path: $rx_bytes_path"
    echo "DEBUG: tx_bytes_path: $tx_bytes_path"
fi