selftests: openvswitch: add a simple test for tunnel metadata

This test ensures that upon receiving decapsulated packets from a
tunnel interface in openvswitch, the tunnel metadata fields are
properly populated. This partially covers interoperability of the
kernel tunnel ports and openvswitch tunnels (LWT) and parsing and
formatting of the tunnel metadata fields of the openvswitch netlink
uAPI. Doing so, this test also ensures that fields and flags are
properly extracted during decapsulation by the tunnel core code,
serving as a regression test for the previously fixed issue with the
DF bit not being extracted from the outer IP header.

The ovs-dpctl.py script already supports all that is necessary for
the tunnel ports for this test, so we only need to adjust the
ovs_add_if() function to pass the '-t' port type argument in order
to be able to create tunnel ports in the openvswitch datapath.

Reviewed-by: Aaron Conole <[e-mail]>
Signed-off-by: Ilya Maximets <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/net/openvswitch/openvswitch.sh

···
 	nat_related_v4				ip4-nat-related: ICMP related matches work with SNAT
 	netlink_checks				ovsnl: validate netlink attrs and settings
 	upcall_interfaces			ovs: test the upcall interfaces
+	tunnel_metadata				ovs: test extraction of tunnel metadata
 	drop_reason				drop: test drop reasons are emitted
 	psample					psample: Sampling packets with psample"
 
···
 }
 
 ovs_add_if () {
-	info "Adding IF to DP: br:$2 if:$3"
-	if [ "$4" != "-u" ]; then
-		ovs_sbx "$1" python3 $ovs_base/ovs-dpctl.py add-if "$2" "$3" \
-		    || return 1
+	info "Adding IF to DP: br:$3 if:$4 ($2)"
+	if [ "$5" != "-u" ]; then
+		ovs_sbx "$1" python3 $ovs_base/ovs-dpctl.py add-if \
+		    -t "$2" "$3" "$4" || return 1
 	else
 		python3 $ovs_base/ovs-dpctl.py add-if \
-		    -u "$2" "$3" >$ovs_dir/$3.out 2>$ovs_dir/$3.err &
+		    -u -t "$2" "$3" "$4" >$ovs_dir/$4.out 2>$ovs_dir/$4.err &
 		pid=$!
 		on_exit "ovs_sbx $1 kill -TERM $pid 2>/dev/null"
 	fi
···
 	fi
 
 	if [ "$7" != "-u" ]; then
-		ovs_add_if "$1" "$2" "$4" || return 1
+		ovs_add_if "$1" "netdev" "$2" "$4" || return 1
 	else
-		ovs_add_if "$1" "$2" "$4" -u || return 1
+		ovs_add_if "$1" "netdev" "$2" "$4" -u || return 1
 	fi
 
 	if [ $TRACING -eq 1 ]; then
···
 	    >$ovs_dir/arping.stdout 2>$ovs_dir/arping.stderr
 
 	grep -E "MISS upcall\[0/yes\]: .*arp\(sip=172.31.110.1,tip=172.31.110.20,op=1,sha=" $ovs_dir/left0.out >/dev/null 2>&1 || return 1
+	return 0
+}
+
+ovs_add_kernel_tunnel() {
+	local sbxname=$1; shift
+	local ns=$1; shift
+	local tnl_type=$1; shift
+	local name=$1; shift
+	local addr=$1; shift
+
+	info "setting up kernel ${tnl_type} tunnel ${name}"
+	ovs_sbx "${sbxname}" ip -netns ${ns} link add dev ${name} type ${tnl_type} $* || return 1
+	on_exit "ovs_sbx ${sbxname} ip -netns ${ns} link del ${name} >/dev/null 2>&1"
+	ovs_sbx "${sbxname}" ip -netns ${ns} addr add dev ${name} ${addr} || return 1
+	ovs_sbx "${sbxname}" ip -netns ${ns} link set dev ${name} mtu 1450 up || return 1
+}
+
+test_tunnel_metadata() {
+	which arping >/dev/null 2>&1 || return $ksft_skip
+
+	sbxname="test_tunnel_metadata"
+	sbx_add "${sbxname}" || return 1
+
+	info "setting up new DP"
+	ovs_add_dp "${sbxname}" tdp0 -V 2:1 || return 1
+
+	ovs_add_netns_and_veths "${sbxname}" tdp0 tns left0 l0 \
+		172.31.110.1/24 || return 1
+
+	info "removing veth interface from openvswitch and setting IP"
+	ovs_del_if "${sbxname}" tdp0 left0 || return 1
+	ovs_sbx "${sbxname}" ip addr add 172.31.110.2/24 dev left0 || return 1
+	ovs_sbx "${sbxname}" ip link set left0 up || return 1
+
+	info "setting up tunnel port in openvswitch"
+	ovs_add_if "${sbxname}" "vxlan" tdp0 ovs-vxlan0 -u || return 1
+	on_exit "ovs_sbx ${sbxname} ip link del ovs-vxlan0"
+	ovs_wait ip link show ovs-vxlan0 &>/dev/null || return 1
+	ovs_sbx "${sbxname}" ip link set ovs-vxlan0 up || return 1
+
+	configs=$(echo '
+	    1 172.31.221.1/24 1155332 32   set   udpcsum flags\(df\|csum\)
+	    2 172.31.222.1/24 1234567 45   set noudpcsum flags\(df\)
+	    3 172.31.223.1/24 1020304 23 unset   udpcsum flags\(csum\)
+	    4 172.31.224.1/24 1357986 15 unset noudpcsum' | sed '/^$/d')
+
+	while read -r i addr id ttl df csum flags; do
+		ovs_add_kernel_tunnel "${sbxname}" tns vxlan vxlan${i} ${addr} \
+			remote 172.31.110.2 id ${id} dstport 4789 \
+			ttl ${ttl} df ${df} ${csum} || return 1
+	done <<< "${configs}"
+
+	ovs_wait grep -q 'listening on upcall packet handler' \
+		${ovs_dir}/ovs-vxlan0.out || return 1
+
+	info "sending arping"
+	for i in 1 2 3 4; do
+		ovs_sbx "${sbxname}" ip netns exec tns \
+			arping -I vxlan${i} 172.31.22${i}.2 -c 1 \
+			>${ovs_dir}/arping.stdout 2>${ovs_dir}/arping.stderr
+	done
+
+	info "checking that received decapsulated packets carry correct metadata"
+	while read -r i addr id ttl df csum flags; do
+		arp_hdr="arp\\(sip=172.31.22${i}.1,tip=172.31.22${i}.2,op=1,sha="
+		addrs="src=172.31.110.1,dst=172.31.110.2"
+		ports="tp_src=[0-9]*,tp_dst=4789"
+		tnl_md="tunnel\\(tun_id=${id},${addrs},ttl=${ttl},${ports},${flags}\\)"
+
+		ovs_sbx "${sbxname}" grep -qE "MISS upcall.*${tnl_md}.*${arp_hdr}" \
+			${ovs_dir}/ovs-vxlan0.out || return 1
+	done <<< "${configs}"
+
 	return 0
 }