From 4fb81152933d5498e598b2437c57ca410a804038 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Wed, 24 Nov 2021 15:50:04 +0100
Subject: [PATCH] net_qdisc_nfs_low: Add script

Add script net_qdisc_nfs_low.

usage: /usr/sbin/net_qdisc_nfs_low { start | stop | restart | status }

Called with "start", this script installs a traffic shaping queueing
discipline and filters on the default network interface, which gives nfs
traffic, in which the current system is the client, a lower priority
than other traffic.
---
 install.sh                          |  1 +
 net_qdisc_nfs_low/net_qdisc_nfs_low | 44 +++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100755 net_qdisc_nfs_low/net_qdisc_nfs_low

diff --git a/install.sh b/install.sh
index 5bc75be..0d1ccad 100755
--- a/install.sh
+++ b/install.sh
@@ -230,6 +230,7 @@ install_data prun/pman.1                                  "$DESTDIR$usr_mandir/m
 install_exec crashkernel/startup-crashmemory              "$DESTDIR$usr_sbindir/startup-crashmemory"
 install_data crashkernel/startup-crashmemory.service      "$DESTDIR$systemdunitdir/startup-crashmemory.service"
 install_exec mxsnoop/mxsnoop.sh                           "$DESTDIR$usr_sbindir/mxsnoop.sh"
+install_exec net_qdisc_nfs_low/net_qdisc_nfs_low          "$DESTDIR$usr_sbindir/net_qdisc_nfs_low"
 
 postinstall
 exit
diff --git a/net_qdisc_nfs_low/net_qdisc_nfs_low b/net_qdisc_nfs_low/net_qdisc_nfs_low
new file mode 100755
index 0000000..828d0b1
--- /dev/null
+++ b/net_qdisc_nfs_low/net_qdisc_nfs_low
@@ -0,0 +1,44 @@
+#! /bin/bash
+
+. /etc/local/mxhost.conf
+
+case "$1" in
+	start)
+		tc qdisc add dev $MX_NETDEV root        handle 10: prio
+		tc qdisc add dev $MX_NETDEV parent 10:1 handle 20: sfq # band 0 highest priority
+		tc qdisc add dev $MX_NETDEV parent 10:2 handle 30: sfq # band 2
+		tc qdisc add dev $MX_NETDEV parent 10:3 handle 40: sfq # band 3
+
+		tc filter add dev $MX_NETDEV parent 10: handle 100: protocol ip prio 4 u32 divisor 1
+		tc filter add dev $MX_NETDEV parent 10: handle 100:0:1 protocol ip prio 4 u32 ht 100: match tcp dst 2049 FFFF flowid 10:2
+
+		# The "root filter list is always 800:0.
+		# "match ip firstfrag" compiles to "match 00002000/00003fff at 4" which
+		# includes the "more fragments" flag, so only initial fragments of a
+		# fragmented packet would be selected, not single fragments of an
+		# unfragmented packet. So use "match u32 00000000 00001fff at 4" to
+		# make sure, this is a initial segment and has a tcp header.
+
+		tc filter add dev $MX_NETDEV parent 10: handle 800:0:1 protocol ip prio 4 u32 ht 800: \
+			match ip protocol 06 ff \
+			match u32 00000000 00001fff at 4 \
+			offset at 0 mask 0f00 shift 6 \
+			link 100:
+		tc filter add dev $MX_NETDEV parent 10: handle 800:0:2 protocol ip prio 4 u32 ht 800: match u32 0 0 flowid 10:1
+		;;
+	stop)
+		tc filter delete dev $MX_NETDEV
+		tc qdisc delete dev $MX_NETDEV root
+		;;
+	restart)
+		$0 stop
+		$0 start
+		;;
+	status)
+		tc -s qdisc show dev $MX_NETDEV
+		tc -s filter show dev $MX_NETDEV
+		;;
+	*)
+		echo "usage: $0 { start | stop | restart | status }" >&2
+		exit 1
+esac