1 files changed, 57 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/fq_band_pktlimit.sh b/tools/testing/selftests/net/fq_band_pktlimit.sh
new file mode 100755
index 0000000000..24b77bdf41
--- /dev/null
+++ b/tools/testing/selftests/net/fq_band_pktlimit.sh
@@ -0,0 +1,57 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Verify that FQ has a packet limit per band:
+#
+# 1. set the limit to 10 per band
+# 2. send 20 pkts on band A: verify that 10 are queued, 10 dropped
+# 3. send 20 pkts on band A: verify that  0 are queued, 20 dropped
+# 4. send 20 pkts on band B: verify that 10 are queued, 10 dropped
+#
+# Send packets with a 100ms delay to ensure that previously sent
+# packets are still queued when later ones are sent.
+# Use SO_TXTIME for this.
+
+die() {
+	echo "$1"
+	exit 1
+}
+
+# run inside private netns
+if [[ $# -eq 0 ]]; then
+	./in_netns.sh "$0" __subprocess
+	exit
+fi
+
+ip link add type dummy
+ip link set dev dummy0 up
+ip -6 addr add fdaa::1/128 dev dummy0
+ip -6 route add fdaa::/64 dev dummy0
+tc qdisc replace dev dummy0 root handle 1: fq quantum 1514 initial_quantum 1514 limit 10
+
+./cmsg_sender -6 -p u -d 100000 -n 20 fdaa::2 8000
+OUT1="$(tc -s qdisc show dev dummy0 | grep '^\ Sent')"
+
+./cmsg_sender -6 -p u -d 100000 -n 20 fdaa::2 8000
+OUT2="$(tc -s qdisc show dev dummy0 | grep '^\ Sent')"
+
+./cmsg_sender -6 -p u -d 100000 -n 20 -P 7 fdaa::2 8000
+OUT3="$(tc -s qdisc show dev dummy0 | grep '^\ Sent')"
+
+# Initial stats will report zero sent, as all packets are still
+# queued in FQ. Sleep for the delay period (100ms) and see that
+# twenty are now sent.
+sleep 0.1
+OUT4="$(tc -s qdisc show dev dummy0 | grep '^\ Sent')"
+
+# Log the output after the test
+echo "${OUT1}"
+echo "${OUT2}"
+echo "${OUT3}"
+echo "${OUT4}"
+
+# Test the output for expected values
+echo "${OUT1}" | grep -q '0\ pkt\ (dropped\ 10'  || die "unexpected drop count at 1"
+echo "${OUT2}" | grep -q '0\ pkt\ (dropped\ 30'  || die "unexpected drop count at 2"
+echo "${OUT3}" | grep -q '0\ pkt\ (dropped\ 40'  || die "unexpected drop count at 3"
+echo "${OUT4}" | grep -q '20\ pkt\ (dropped\ 40' || die "unexpected accept count at 4"