Detect MTU for tc rather than specify in tcdevices file

git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@3900 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb

Shorewall/changelog.txt

@@ -4,7 +4,7 @@ Changes in 3.2.0 Beta 7
 
 2)  Restore traffic control to 'refresh'.
 
-3)  Add MTU column to /etc/shorewall/tcdevices.
+3)  Detect MTU for entries in /etc/shorewall/tcdevices.
 
 Changes in 3.2.0 Beta 6
 

Shorewall/functions

@@ -978,6 +978,17 @@ find_gateway() {
     done
 }
 
+#
+# Find the value 'mtu' in the passed arguments then echo the next value
+#
+
+find_mtu() {
+    while [ $# -gt 1 ]; do
+	[ "x$1" = xmtu ] && echo $2 && return
+	shift
+    done
+}
+
 #
 # Find the value 'peer' in the passed arguments then echo the next value up to
 # "/"
@@ -1499,6 +1510,20 @@ verify_mark() # $1 = value to test
     verify_mark2 $1 || fatal_error "Invalid Mark or Mask value: $1"
 }
 
+#
+# Detect a device's MTU
+#
+get_device_mtu() # $1 = device
+{
+    local output=$(ip link ls dev $1 2> /dev/null)
+
+    if [ -n "$output" ]; then
+	echo $(find_mtu $output)
+    else
+	echo 1500
+    fi
+}
+
 #
 # Arne Bernin's 'tc4shorewall'
 #
@@ -1534,15 +1559,8 @@ setup_traffic_shaping()
     }
 
     calculate_quantum() {
-	local rate
+	local rate=$(rate_to_kbit $1)
-	rate=$1
+	echo $(( $rate * ( 128 / $r2q ) ))
-	rate=$(rate_to_kbit $rate)
-	rate=$(expr $rate \* 128 / $r2q )
-	if [ $rate -lt $mtu ] ; then
-	    echo $mtu
-	else
-	    echo $rate
-	fi
     }
 
     # get given outbandwidth for device
@@ -1655,12 +1673,14 @@ setup_traffic_shaping()
 	    save_command qt tc qdisc del dev $device ingress
 	fi
 
-	[ x${mtu:--} = x- ] && mtu=1500
-	
-	eval ${dev}_mtu=$mtu
-	
 	run_tc qdisc add dev $device root handle $devnum: htb default 1$defmark
-	run_tc class add dev $device parent $devnum: classid $devnum:1 htb rate $outband mtu $mtu
+
+	if [ $COMMAND = compile ]; then
+	    run_tc "class add dev $device parent $devnum: classid $devnum:1 htb rate $outband mtu \$(get_device_mtu $device)"
+	else
+	    run_tc class add dev $device parent $devnum: classid $devnum:1 htb rate $outband mtu $(get_device_mtu $device)
+	fi
+
 	run_tc qdisc add dev $device handle ffff: ingress
 	run_tc filter add dev $device parent ffff: protocol ip prio 50 u32 match ip src 0.0.0.0/0 police rate ${inband} burst 10k drop flowid :1
 	eval ${dev}_devnum=$devnum
@@ -1668,7 +1688,7 @@ setup_traffic_shaping()
     }
 
     add_tc_class() {
-	local full classid tospair tosmask
+	local full classid tospair tosmask quantum
 	full=$(get_outband_for_dev $device)
 	full=$(rate_to_kbit $full)
 
@@ -1692,7 +1712,6 @@ setup_traffic_shaping()
 
 	dev=$(chain_base $device)
 	eval devnum=\$${dev}_devnum
-	eval mtu=\$${dev}_mtu
 	#
 	# Convert HEX/OCTAL mark representation to decimal
 	#
@@ -1702,7 +1721,18 @@ setup_traffic_shaping()
 
 	[ -n "$devnum" ] || fatal_error "Device $device not defined in $devfile"
 
-	run_tc class add dev $device parent $devnum:1 classid $classid htb rate $rate ceil $ceil prio $prio mtu $mtu quantum $(calculate_quantum $rate)
+	quantum=$(calculate_quantum $rate)
+
+	if [ $COMMAND = compile ]; then
+	    save_command "mtu=\$(get_device_mtu $device)"
+	    save_command "[ \$mtu -gt $quantum ] && quantum=\$mtu || quantum=$quantum" 
+	    run_tc "class add dev $device parent $devnum:1 classid $classid htb rate $rate ceil $ceil prio $prio mtu \$mtu quantum \$quantum"
+	else
+	    mtu= $(get_device_mtu $device)
+	    [ $mtu -gt $quantum ] && quantum=$mtu
+	    run_tc class add dev $device parent $devnum:1 classid $classid htb rate $rate ceil $ceil prio $prio mtu $mtu quantum $quantum
+	fi
+
 	run_tc qdisc add dev $device parent $classid handle 1$mark: sfq perturb 10
 	# add filters
 	if [ -n "$CLASSIFY_TARGET" ]; then
@@ -1741,9 +1771,9 @@ setup_traffic_shaping()
 	[ $COMMAND = compile ] && save_progress_message "Setting up Traffic Control..."
 	progress_message2 "$DOING $devfile..."
 
-	while read device inband outband mtu; do
+	while read device inband outband; do
-	    expandv device inband outband mtu
+	    expandv device inband outband
-	    tcdev="$device $inband $outband $mtu"
+	    tcdev="$device $inband $outband"
 	    add_root_tc
 	    progress_message_and_save "   TC Device $tcdev defined."
 	done < $TMP_DIR/tcdevices

Shorewall/releasenotes.txt

@@ -36,9 +36,9 @@ Other changes in 3.2.0 Beta 7
 
 1)  'shorewall refresh' once again refreshes the tcrules and traffic shaping.
 
-2)  An MTU column has been added to /etc/shorewall/tcdevices that allows
+2)  Shorewall will now attempt to detect the MTU of devices listed in
-    specification of the MTU to use for traffic-shaping. If not specified or
+    /etc/shorewall/tcdevices and will use the detected MTU in setting
-    if specified as '-' then 1500 is assumed.
+    up traffic shaping.
 
 Migration Considerations:
 

Shorewall/tcdevices

@@ -51,9 +51,6 @@
 #			speed, and make sure there is NO space between the
 #			number and the unit.
 #
-#	MTU		The device's MTU. If not specified, a value of 1500
-#			is assumed.
-#
 #	Example 1:	Suppose you are using PPP over Ethernet (DSL)
 #			and ppp0 is the interface for this. The
 #			device has an outgoing bandwidth of 500kbit and an
@@ -62,5 +59,5 @@
 #
 #
 ###############################################################################
-#INTERFACE	IN-BANDWITH	OUT-BANDWIDTH		MTU
+#INTERFACE	IN-BANDWITH	OUT-BANDWIDTH
 #LAST LINE -- ADD YOUR ENTRIES BEFORE THIS ONE -- DO NOT REMOVE