selftests/bpf: extend bpf tunnel test with tso

Segmentation offload takes a longer path. Verify that the feature
works with large packets.

The test succeeds if not setting dodgy in bpf_skb_adjust_room, as veth
TSO is permissive.

If not setting SKB_GSO_DODGY, this enables tunneled TSO offload on
supporting NICs.

The feature sets SKB_GSO_DODGY because the caller is untrusted. As a
result the packets traverse through the gso stack at least up to TCP.
And fail the gso_type validation, such as the skb->encapsulation check
in gre_gso_segment and the gso_type checks introduced in commit
418e897e07 ("gso: validate gso_type on ipip style tunnel").

This will be addressed in a follow-on feature patch. In the meantime,
disable the new gso tests.

Changes v1->v2:
  - not all netcat versions support flag '-q', use timeout instead

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/test_tc_tunnel.sh

@@ -15,6 +15,8 @@ readonly ns2_v4=192.168.1.2
 readonly ns1_v6=fd::1
 readonly ns2_v6=fd::2
 
+readonly infile="$(mktemp)"
+readonly outfile="$(mktemp)"
 
 setup() {
 	ip netns add "${ns1}"
@@ -23,6 +25,8 @@ setup() {
 	ip link add dev veth1 mtu 1500 netns "${ns1}" type veth \
 	      peer name veth2 mtu 1500 netns "${ns2}"
 
+	ip netns exec "${ns1}" ethtool -K veth1 tso off
+
 	ip -netns "${ns1}" link set veth1 up
 	ip -netns "${ns2}" link set veth2 up
 
@@ -32,58 +36,86 @@ setup() {
 	ip -netns "${ns2}" -6 addr add "${ns2_v6}/64" dev veth2 nodad
 
 	sleep 1
+
+	dd if=/dev/urandom of="${infile}" bs="${datalen}" count=1 status=none
 }
 
 cleanup() {
 	ip netns del "${ns2}"
 	ip netns del "${ns1}"
+
+	if [[ -f "${outfile}" ]]; then
+		rm "${outfile}"
+	fi
+	if [[ -f "${infile}" ]]; then
+		rm "${infile}"
+	fi
 }
 
 server_listen() {
-	ip netns exec "${ns2}" nc "${netcat_opt}" -l -p "${port}" &
+	ip netns exec "${ns2}" nc "${netcat_opt}" -l -p "${port}" > "${outfile}" &
+	server_pid=$!
 	sleep 0.2
 }
 
 client_connect() {
-	ip netns exec "${ns1}" nc "${netcat_opt}" -z -w 1 "${addr2}" "${port}"
+	ip netns exec "${ns1}" timeout 2 nc "${netcat_opt}" -w 1 "${addr2}" "${port}" < "${infile}"
 	echo $?
 }
 
+verify_data() {
+	wait "${server_pid}"
+	# sha1sum returns two fields [sha1] [filepath]
+	# convert to bash array and access first elem
+	insum=($(sha1sum ${infile}))
+	outsum=($(sha1sum ${outfile}))
+	if [[ "${insum[0]}" != "${outsum[0]}" ]]; then
+		echo "data mismatch"
+		exit 1
+	fi
+}
+
 set -e
 
 # no arguments: automated test, run all
 if [[ "$#" -eq "0" ]]; then
 	echo "ipip"
-	$0 ipv4 ipip
+	$0 ipv4 ipip 100
 
 	echo "ip6ip6"
-	$0 ipv6 ip6tnl
+	$0 ipv6 ip6tnl 100
 
 	echo "ip gre"
-	$0 ipv4 gre
+	$0 ipv4 gre 100
 
 	echo "ip6 gre"
-	$0 ipv6 ip6gre
+	$0 ipv6 ip6gre 100
+
+	# disabled until passes SKB_GSO_DODGY checks
+	# echo "ip gre gso"
+	# $0 ipv4 gre 2000
+
+	# disabled until passes SKB_GSO_DODGY checks
+	# echo "ip6 gre gso"
+	# $0 ipv6 ip6gre 2000
 
 	echo "OK. All tests passed"
 	exit 0
 fi
 
-if [[ "$#" -ne "2" ]]; then
+if [[ "$#" -ne "3" ]]; then
 	echo "Usage: $0"
-	echo "   or: $0 <ipv4|ipv6> <tuntype>"
+	echo "   or: $0 <ipv4|ipv6> <tuntype> <data_len>"
 	exit 1
 fi
 
 case "$1" in
 "ipv4")
-	readonly tuntype=$2
 	readonly addr1="${ns1_v4}"
 	readonly addr2="${ns2_v4}"
 	readonly netcat_opt=-4
 	;;
 "ipv6")
-	readonly tuntype=$2
 	readonly addr1="${ns1_v6}"
 	readonly addr2="${ns2_v6}"
 	readonly netcat_opt=-6
@@ -94,7 +126,10 @@ case "$1" in
 	;;
 esac
 
-echo "encap ${addr1} to ${addr2}, type ${tuntype}"
+readonly tuntype=$2
+readonly datalen=$3
+
+echo "encap ${addr1} to ${addr2}, type ${tuntype}, len ${datalen}"
 
 trap cleanup EXIT
 
@@ -104,6 +139,7 @@ setup
 echo "test basic connectivity"
 server_listen
 client_connect
+verify_data
 
 # clientside, insert bpf program to encap all TCP to port ${port}
 # client can no longer connect
@@ -123,6 +159,7 @@ ip netns exec "${ns2}" ip link add dev testtun0 type "${tuntype}" \
 ip netns exec "${ns2}" ip link set dev testtun0 up
 echo "test bpf encap with tunnel device decap"
 client_connect
+verify_data
 
 # serverside, use BPF for decap
 ip netns exec "${ns2}" ip link del dev testtun0
@@ -132,5 +169,6 @@ ip netns exec "${ns2}" tc filter add dev veth2 ingress \
 server_listen
 echo "test bpf encap with bpf decap"
 client_connect
+verify_data
 
 echo OK