script contributed by mike perry to make tor traffic low priority

svn:r11205

contrib/linux-tor-prio.sh

@@ -0,0 +1,127 @@
+#!/bin/bash
+# Writen by Mike Perry 
+# Based on instructions from Dan Singletary's ADSL Bandwidth Management HOWTO
+# http://www.faqs.org/docs/Linux-HOWTO/ADSL-Bandwidth-Management-HOWTO.html
+# This script is Public Domain. 
+
+# The following configuration works well for a ~5Mbit tor node. It requires
+# that you place your Tor traffic on a seperate IP from the rest of your
+# traffic.
+
+# BEGIN DEVICE PARAMETERS
+
+DEV=eth0
+BOX_IP=42.42.42.42 
+TOR_IP=43.43.43.43
+
+# Average ping to most places on the net, milliseconds
+RTT_LATENCY=40
+
+# END DEVICE PARAMETERS
+# BEGIN UPLOAD PARAMETERS
+
+# RATE_UP must be less than your connection's upload capacity. If it is
+# larger, then the bottleneck will be at your router's queue, which you
+# do not control. This will cause congestion and a revert to normal TCP
+# fairness no matter what the queing priority is.
+RATE_UP=5000
+
+# RATE_UP_TOR is the minimum speed your Tor connections will have. 
+# They will have at least this much bandwidth for upload
+RATE_UP_TOR=1500
+
+# RATE_UP_TOR_CEIL is the maximum rate allowed for all Tor trafic
+RATE_UP_TOR_CEIL=5000
+
+CHAIN=OUTPUT
+#CHAIN=PREROUTING
+#CHAIN=POSTROUTING
+
+# END UPLOAD PARAMETERS
+
+MTU=1500
+AVG_PKT=900
+
+# END USER TUNABLE PARAMETERS
+
+# The queue size should be no larger than your bandwidth-delay
+# product. This is RT latency*bandwidth/MTU/2
+
+BDP=$(expr $RTT_LATENCY \* $RATE_UP / $AVG_PKT) 
+
+# Further research indicates that the BDP calculations should use
+# RTT/sqrt(n) where n is the expected number of active connections..
+
+BDP=$(expr $BDP / 4)
+
+if [ "$1" = "status" ]
+then
+        echo "[qdisc]"
+        tc -s qdisc show dev $DEV
+        tc -s qdisc show dev imq0
+        echo "[class]"
+        tc -s class show dev $DEV
+        tc -s class show dev imq0
+        echo "[filter]"
+        tc -s filter show dev $DEV
+        tc -s filter show dev imq0
+        echo "[iptables]"
+        iptables -t mangle -L TORSHAPER-OUT -v -x 2> /dev/null
+        exit
+fi
+
+
+# Reset everything to a known state (cleared)
+tc qdisc del dev $DEV root 2> /dev/null > /dev/null
+tc qdisc del dev imq0 root 2> /dev/null > /dev/null
+iptables -t mangle -D POSTROUTING -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
+iptables -t mangle -D PREROUTING -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
+iptables -t mangle -D OUTPUT -o $DEV -j TORSHAPER-OUT 2> /dev/null > /dev/null
+iptables -t mangle -F TORSHAPER-OUT 2> /dev/null > /dev/null
+iptables -t mangle -X TORSHAPER-OUT 2> /dev/null > /dev/null
+ip link set imq0 down 2> /dev/null > /dev/null
+rmmod imq 2> /dev/null > /dev/null
+
+if [ "$1" = "stop" ] 
+then 
+        echo "Shaping removed on $DEV."
+        exit
+fi
+
+# Outbound Shaping (limits total bandwidth to RATE_UP)
+
+ip link set dev $DEV qlen $BDP
+
+# Add HTB root qdisc, default is high prio
+tc qdisc add dev $DEV root handle 1: htb default 20
+
+# Add main rate limit class
+tc class add dev $DEV parent 1: classid 1:1 htb rate ${RATE_UP}kbit
+
+# Create the two classes, giving Tor at least RATE_UP_TOR kbit and capping
+# total upstream at RATE_UP so the queue is under our control.
+tc class add dev $DEV parent 1:1 classid 1:20 htb rate $(expr $RATE_UP - $RATE_UP_TOR)kbit ceil ${RATE_UP}kbit prio 0
+tc class add dev $DEV parent 1:1 classid 1:21 htb rate $[$RATE_UP_TOR]kbit ceil ${RATE_UP_TOR_CEIL}kbit prio 10
+
+# Start up pfifo
+tc qdisc add dev $DEV parent 1:20 handle 20: pfifo limit $BDP
+tc qdisc add dev $DEV parent 1:21 handle 21: pfifo limit $BDP
+
+# filter traffic into classes by fwmark
+tc filter add dev $DEV parent 1:0 prio 0 protocol ip handle 20 fw flowid 1:20
+tc filter add dev $DEV parent 1:0 prio 0 protocol ip handle 21 fw flowid 1:21
+
+# add TORSHAPER-OUT chain to the mangle table in iptables
+iptables -t mangle -N TORSHAPER-OUT
+iptables -t mangle -I $CHAIN -o $DEV -j TORSHAPER-OUT
+
+# Set firewall marks
+# Low priority to Tor IP
+iptables -t mangle -A TORSHAPER-OUT -s $TOR_IP -j MARK --set-mark 21
+
+# High prio for everything else
+# Don't bother to use BOX_IP. Box probably has other IPs too...
+#iptables -t mangle -A TORSHAPER-OUT -s $BOX_IP -j MARK --set-mark 20 
+iptables -t mangle -A TORSHAPER-OUT -m mark --mark 0 -j MARK --set-mark 20
+
+echo "Outbound shaping added to $DEV.  Rate for Tor upload at least: ${RATE_UP_TOR}Kbyte/sec."