2 files changed, 165 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 590b33e16d9f..55101ed41c52 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -42,6 +42,7 @@ TEST_PROGS := \
 	fib_rule_tests.sh \
 	fib_tests.sh \
 	fin_ack_lat.sh \
+	fou_gre_gro.sh \
 	fou_mcast_encap.sh \
 	fq_band_pktlimit.sh \
 	gre_gso.sh \
diff --git a/tools/testing/selftests/net/fou_gre_gro.sh b/tools/testing/selftests/net/fou_gre_gro.sh
new file mode 100755
index 000000000000..21ed50f647ae
--- /dev/null
+++ b/tools/testing/selftests/net/fou_gre_gro.sh
@@ -0,0 +1,164 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test that GRE packets carried over UDP (FOU or GUE) get through when the
+# receiver merges them with GRO.
+#
+# Send bulk TCP through such tunnels with GRO on at the receiver, and
+# segmentation off at the sender so the receiver gets wire-sized packets
+# to merge, and check that the receiver counts no UDP errors (UdpInErrors
+# or Udp6InErrors). Also check that GRO really merged packets, by comparing
+# the UDP datagrams the receiver delivered with the packets its veth
+# received, so that a setup where GRO doesn't engage skips rather than
+# passes.
+
+source lib.sh
+
+NSEND=""
+NRECV=""
+
+FOU_PORT=5555
+TCP_PORT=9000
+SIZE_MB=4
+
+TUN_S=192.168.99.1
+TUN_R=192.168.99.2
+
+cleanup() {
+	cleanup_all_ns
+}
+
+trap cleanup EXIT
+
+# setup_tunnel creates the namespaces, the veth between them and a GRE
+# tunnel over UDP encapsulation $1 (fou or gue) over IPv$2. It returns
+# $ksft_skip if the kernel or iproute2 can't set it up.
+setup_tunnel() {
+	local encap=$1
+	local family=$2
+	local type=gre
+	local addr_s=10.0.0.1
+	local addr_r=10.0.0.2
+	local fou_args="ipproto 47"
+
+	if [ "$encap" = gue ]; then
+		fou_args=gue
+	fi
+	if [ "$family" = 6 ]; then
+		type=ip6gre
+		addr_s=2001:db8::1
+		addr_r=2001:db8::2
+		fou_args="$fou_args -6"
+	fi
+
+	setup_ns NSEND NRECV || return "$ksft_skip"
+
+	ip link add veth_s netns "$NSEND" type veth \
+		peer name veth_r netns "$NRECV" || return "$ksft_skip"
+	ip -n "$NSEND" addr add 10.0.0.1/24 dev veth_s
+	ip -n "$NRECV" addr add 10.0.0.2/24 dev veth_r
+	ip -n "$NSEND" addr add 2001:db8::1/64 dev veth_s nodad
+	ip -n "$NRECV" addr add 2001:db8::2/64 dev veth_r nodad
+	ip -n "$NSEND" link set veth_s up
+	ip -n "$NRECV" link set veth_r up
+
+	ip netns exec "$NRECV" ethtool -K veth_r gro on || return "$ksft_skip"
+	ip netns exec "$NSEND" ethtool -K veth_s tso off gso off \
+		tx-gre-segmentation off tx-gre-csum-segmentation off \
+		tx-udp_tnl-segmentation off tx-udp_tnl-csum-segmentation off ||
+		return "$ksft_skip"
+
+	# shellcheck disable=SC2086 # $fou_args is several arguments
+	ip netns exec "$NSEND" ip fou add port "$FOU_PORT" $fou_args ||
+		return "$ksft_skip"
+	# shellcheck disable=SC2086
+	ip netns exec "$NRECV" ip fou add port "$FOU_PORT" $fou_args ||
+		return "$ksft_skip"
+	ip -n "$NSEND" link add gre_t type "$type" \
+		local "$addr_s" remote "$addr_r" \
+		encap "$encap" encap-sport auto encap-dport "$FOU_PORT" ||
+		return "$ksft_skip"
+	ip -n "$NRECV" link add gre_t type "$type" \
+		local "$addr_r" remote "$addr_s" \
+		encap "$encap" encap-sport auto encap-dport "$FOU_PORT" ||
+		return "$ksft_skip"
+
+	ip -n "$NSEND" addr add "$TUN_S/30" dev gre_t
+	ip -n "$NRECV" addr add "$TUN_R/30" dev gre_t
+	ip -n "$NSEND" link set gre_t up
+	ip -n "$NRECV" link set gre_t up
+}
+
+# recv_counter prints the sum of the receiver's nstat counters "$@".
+recv_counter() {
+	ip netns exec "$NRECV" nstat -az "$@" |
+		awk '!/^#/ { n += $2 } END { print n + 0 }'
+}
+
+run_test() {
+	local encap=$1
+	local family=$2
+	local name="GRO of GRE in ${encap^^} over IPv$family"
+	local datagrams
+	local packets
+	local errors
+	local pid
+	local rc
+
+	RET=0
+
+	if ! setup_tunnel "$encap" "$family"; then
+		log_test_skip "$name"
+		cleanup_all_ns
+		return
+	fi
+
+	ip netns exec "$NRECV" socat -u \
+		TCP4-LISTEN:"$TCP_PORT",bind="$TUN_R",reuseaddr OPEN:/dev/null &
+	pid=$!
+	wait_local_port_listen "$NRECV" "$TCP_PORT" tcp
+
+	# The timeout only bounds failing runs; passing ones take under a second.
+	dd if=/dev/zero bs=1M count="$SIZE_MB" 2>/dev/null |
+		ip netns exec "$NSEND" timeout 20 \
+			socat -u STDIN TCP4:"$TUN_R":"$TCP_PORT"
+	rc=$?
+
+	# Check the UDP error count rather than the duration, which depends
+	# on the machine.
+	errors=$(recv_counter UdpInErrors Udp6InErrors)
+	check_err "$errors" "$errors UDP errors at the receiver"
+	check_err "$rc" "transfer failed"
+
+	# Without errors, a pass only means something if GRO merged packets:
+	# then the encapsulation socket sees far fewer datagrams than the
+	# veth received packets.
+	datagrams=$(recv_counter UdpInDatagrams Udp6InDatagrams)
+	packets=$(ip netns exec "$NRECV" \
+		cat /sys/class/net/veth_r/statistics/rx_packets)
+	if [ "$RET" -eq 0 ] && [ $((datagrams * 2)) -gt "$packets" ]; then
+		ret_set_ksft_status "$ksft_skip" \
+			"GRO didn't merge: $datagrams UDP datagrams from $packets packets"
+	fi
+
+	log_test "$name"
+	kill "$pid" 2>/dev/null
+	wait "$pid" 2>/dev/null
+	cleanup_all_ns
+}
+
+require_command socat
+require_command ethtool
+require_command nstat
+
+modprobe -q fou
+modprobe -q ip_gre
+modprobe -q fou6
+modprobe -q ip6_gre
+
+run_test fou 4
+run_test gue 4
+run_test fou 6
+run_test gue 6
+
+exit "$EXIT_STATUS"